JP2015142894A - separation membrane element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a separation membrane element for forming a permeation side flow channel having high efficiency and stability, having removal performance of removing a separated component and high permeation performance, and high efficiency.SOLUTION: The separation membrane element comprises: a water collection pipe; and plural separation membrane leaves wound around the water collection pipe in a laminated state each other. Each separation membrane leaf has plural flow channel materials on a surface of a permeation side of fluid and in a width direction of the separation membrane leaf, and bottom side positions of the flow channel materials of one separation membrane leaf and bottom side positions of the flow channel materials of at least one of other separation membrane leaves are deviated in the width direction.

Description

  The present invention relates to a separation membrane element that separates components contained in a fluid such as liquid or gas.

  In the technology for removing ionic substances contained in seawater, brine, and the like, in recent years, the use of separation methods using separation membrane elements has been expanded from the viewpoint of energy saving and resource saving. Separation membranes used in separation methods using separation membrane elements are classified into microfiltration membranes, ultrafiltration membranes, nanofiltration membranes, reverse osmosis membranes, and forward osmosis membranes in terms of their pore sizes and separation functions. These membranes are used, for example, in the production of drinking water from seawater, brackish water and water containing harmful substances, industrial ultrapure water, wastewater treatment and recovery of valuable materials. It is properly used depending on the separation component and separation performance.

  There are various types of separation membrane elements, but they are common in that raw water is supplied to one surface of the separation membrane and a permeated fluid is obtained from the other surface. The separation membrane element includes a large number of bundled separation membranes so that the membrane area per one separation membrane element is increased, that is, the amount of permeate fluid obtained per one separation membrane element is large. It is formed to become. As the separation membrane element, various shapes 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 according to applications and purposes.

  For example, spiral separation membrane elements are widely used for reverse osmosis filtration. The spiral separation membrane element includes a center tube and a laminate wound around the center tube. The laminate is a supply-side flow path material that supplies raw water (that is, treated water) to the separation membrane surface, a separation membrane that separates components contained in the raw water, and a permeation side that is separated from the supply-side fluid through the separation membrane. It is formed by laminating a permeate-side channel material for guiding the fluid to the central tube. The spiral separation membrane element is preferably used in that a large amount of permeated fluid can be taken out because pressure can be applied to the raw water.

  In the spiral type separation membrane element, in general, a polymer net is mainly used as a supply-side channel material in order to form a supply-side fluid channel. In addition, a stacked type separation membrane is used as the separation membrane. Laminated separation membranes are a separation functional layer (porous support layer) made of a crosslinked polymer such as polyamide, a porous resin layer made of a polymer such as polysulfone, polyethylene terephthalate, etc., laminated from the supply side to the permeate side A non-woven substrate made of the above polymer is provided. Further, as the permeation 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 permeation side channel.

  In recent years, due to the increasing demand for reducing the fresh water generation cost, there has been a demand for higher performance of the separation membrane element. For example, in order to improve the separation performance of the separation membrane element and increase the amount of permeated fluid per unit time, it has been proposed to improve the performance of the separation membrane element member such as each flow path member.

  Specifically, Patent Document 1 proposes a separation membrane element that includes an unevenly shaped sheet as a permeate-side channel material. In Patent Document 2, a separation membrane that does not require a supply-side passage material such as a net or a permeation-side passage material such as a tricot by disposing a passage material composed of an elastomer called a vane in the separation membrane. Elements have been proposed. Patent Document 3 proposes a highly durable separation membrane element in which the channel material is firmly fixed to the separation membrane.

JP 2006-247453 A Special table 2012-518538 gazette International Publication No. 2013-047744

  Despite the various proposals described above, the conventional separation membrane element has room for improvement because the present invention has insufficient separation performance and long-term performance stability. An object of this invention is to provide the separation membrane element which can fully improve performance.

  In order to achieve the above object, a water collecting pipe and a plurality of separation membrane leaves wound around each other around the water collecting pipe are provided, and each of the separation membrane leaves has a fluid permeation side. On the surface, a plurality of flow path materials are provided in the width direction of the separation membrane leaf, and the bottom position of the flow path material of one separation membrane leaf and the bottom position of the flow path material of at least one other separation membrane leaf Are shifted in the width direction.

  According to the present invention, a high-efficiency and stable permeation-side flow path can be formed, and a high-performance, high-efficiency separation membrane element having separation component removal performance and high permeation performance can be obtained.

An exploded perspective view showing one embodiment of a separation membrane leaf The top view which shows the separation membrane provided with the flow-path material provided continuously in the length direction (2nd direction) of the separation membrane. The top view which shows the separation membrane provided with the flow-path material provided discontinuously in the length direction (2nd direction) of the separation membrane 2 and 3 cross-sectional view in the width direction of the separation membrane FIG. 4 is a cross-sectional view and a perspective view of a plurality of separation membrane leaves in the separation membrane width direction of FIG. 2 and FIG. 3, (a) is a sectional view with respect to a plane perpendicular to the separation membrane leaf membrane surface and parallel to the width direction; b) is a sectional view with respect to a plane perpendicular to the separation membrane leaf membrane surface and parallel to the width direction, and (c) is an inner edge of the separation membrane leaf and an inner edge of the separation membrane leaf adjacent to the separation membrane leaf. Perspective view showing angle formed It is a perspective view which shows one form of a separation membrane element, (a) is an expansion | deployment perspective view which shows the state which winds a separation membrane leaf around a water collection pipe, (b) is a perspective view which shows the completed separation membrane element Side view of separation membrane Sectional drawing which shows schematic structure of the main part of a separation membrane

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

[1. Separation membrane)
(1-1) Overview of Separation Membrane A separation membrane is a membrane that can separate components in a fluid supplied to the surface of the separation membrane and obtain a permeated fluid that has permeated the separation membrane. The separation membrane includes a separation membrane main body and a flow path material disposed on the separation membrane main body.

  As an example of such a separation membrane, an exploded perspective view of a separation membrane leaf including an example of an embodiment of the separation membrane of the present invention is shown in FIG. In FIG. 1, the separation membrane leaf 4 includes the separation membrane 1 and the separation membrane 7, and is arranged so that the supply side surface 21 of the separation membrane 1 and the supply side surface 71 of the separation membrane 7 face each other. The separation membrane 1 includes a separation membrane body 2 and a permeate-side channel material 31. The channel material 31 is provided on the transmission side surface 22 so as to form a channel. Details of each part of the separation membrane 1 will be described later. The separation membrane body 2 includes a supply-side surface 21 and a permeation-side surface 22. The separation membrane 7 includes a supply-side surface 71 and a permeation-side surface 72.

  In the present specification, the “supply side surface” of the separation membrane body means a surface on the side to which raw water (fluid) is supplied out of the two surfaces of the separation membrane body. The “transmission side surface” means the opposite side surface. As will be described later, when the separation membrane main body includes the base material 201 and the separation functional layer 203 as shown in FIG. 8, generally, the surface on the separation functional layer side is the surface 21 on the supply side, The surface on the side is the surface 22 on the transmission side.

  In FIG. 8, the separation membrane body 2 is described as a laminate of a base material 201, a porous support layer 202 and a separation functional layer 203. As described above, the surface open to the outside of the separation functional layer 203 is the surface 21 on the fluid supply side, and the surface open to the outside of the base material 201 is the surface 22 on the fluid permeation side.

  The x-axis, y-axis, and z-axis direction axes are shown in the figure. The x-axis may be referred to as a first direction and the y-axis may be referred to as a second direction. As shown in FIG. 1 and the like, the separation membrane main body 2 is rectangular, and the first direction and the second direction are parallel to the outer edge of the separation membrane main body 2. The first direction may be referred to as the width direction, and the second direction may be referred to as the length direction. In FIG. 1, the first direction (width direction) is represented by a CD arrow, and the second direction (length direction) is represented by an MD arrow. The first direction and the second direction are orthogonal, the width direction and the length direction are orthogonal, and CD and MD are orthogonal.

(1-2) Separation membrane body <Overview>
As the separation membrane body, a membrane having separation performance according to the method of use, purpose and the like is used. The separation membrane body may be formed of a single layer or a composite membrane including a separation functional layer and a substrate. Further, as shown in FIG. 8, in the composite membrane, a porous support layer 202 may be formed between the separation functional layer 203 and the base material 201.

<Separation function layer>
The thickness of the separation functional layer is not limited to a specific numerical value, but is preferably 5 nm or more and 3000 nm or less in terms of separation performance and transmission performance. In particular, in the case of a reverse osmosis membrane, a forward osmosis membrane, and a nanofiltration membrane, the thickness is preferably 5 nm or more and 300 nm or less.

  The thickness of the separation functional layer can be based on a normal method for measuring the thickness of the separation membrane. 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 can be made at intervals of 50 nm in the cross-sectional length direction of the pleat structure located above the porous support layer, the number of pleats can be measured, and the average can be obtained. it can.

  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 cellulose, polyvinylidene fluoride, polyether sulfone, or polysulfone as a main component is preferably applied as the separation functional layer.

  In this document, “X contains Y as a main component” means that the Y content in X is 50% by mass, 70% by mass, 80% by mass, 90% by mass, or 95% by mass. It means that it is more than%. 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.

  On the other hand, as the separation functional layer supported by the porous support 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, and the like are preferably used in terms of excellent separation performance of components in raw water. 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 is formed by interfacial polycondensation of a polyfunctional amine and a polyfunctional acid halide by a known method. For example, by applying a polyfunctional amine aqueous solution to the porous support layer, removing the excess amine aqueous solution with an air knife or the like, and then applying an organic solvent solution containing a polyfunctional acid halide, the polyamide separation functional layer Is obtained.

Further, the separation functional layer may have an organic-inorganic hybrid structure containing Si element or the like. The separation functional layer having an organic-inorganic hybrid structure can contain, for example, the following compounds (A) and (B):
(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) and having an ethylenically unsaturated group Compound.

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), and-At least 1 sort (s) of 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 to the porous support layer. In order to condense the hydrolyzable group after removing the excess reaction solution, heat treatment may be performed. As a polymerization method of the ethylenically unsaturated groups of the compound (A) and the compound (B), 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 or an alkaline aqueous solution, for example, before use.

<Porous support layer>
The porous support layer is a layer that supports the separation functional layer, and is also referred to as a porous resin layer.
Although the material used for a porous support layer and its shape are not specifically limited, For example, you may form on a board | substrate with porous resin. As the porous support layer, polysulfone, cellulose acetate, polyvinyl chloride, epoxy resin or a mixture and laminate of them is used, and polysulfone with high chemical, mechanical and thermal stability and easy to control pore size. Is preferably used.

  The porous support layer gives mechanical strength to the separation membrane, and does not have separation performance like a separation membrane for components 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. Particularly in terms 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 equivalent circle diameter of 3 nm to 50 nm. .

  The thickness of the porous support layer is not particularly limited, but is preferably in the range of 20 μm to 500 μm, more preferably 30 μm to 300 μm, for reasons such as giving strength to the separation membrane.

  The form 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. The sample is thinly coated with platinum, platinum-palladium, or ruthenium tetrachloride, preferably ruthenium tetrachloride, and observed with a high-resolution field emission scanning electron microscope (UHR-FE-SEM) at an acceleration voltage of 3 kV to 6 kV. A Hitachi S-900 electron microscope or the like 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 are average values, and the thickness of the porous support layer is measured at intervals of 20 μm in a direction perpendicular to the thickness direction by cross-sectional observation, and is an average value of 20 points. 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, the porous support layer is prepared by pouring an N, N-dimethylformamide (hereinafter referred to as DMF) solution of the above polysulfone into a constant thickness on a substrate to be described later, for example, a densely woven polyester cloth or non-woven cloth. It can be produced by molding and wet coagulating it 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, this polysulfone resin solution is applied to a substrate made of polyester cloth or nonwoven fabric to a substantially constant thickness, and after removing the surface solvent in the air for a certain period of time, the polysulfone is coagulated in the coagulation liquid. Can be obtained.

<Base material>
From the viewpoints of strength, dimensional stability, etc. of the separation membrane body, the separation membrane body can have a substrate. As the base material, it is preferable to use a fibrous base material in terms of strength, unevenness forming ability and fluid permeability.

  As a base material, both a long fiber nonwoven fabric and a short fiber nonwoven fabric can be used preferably. In particular, since the long fiber nonwoven fabric has excellent film-forming properties, when the polymer solution is cast, the solution penetrates through the permeation, the porous support layer peels off, and Can suppress the film from becoming non-uniform due to fluffing of the substrate and the like, 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, compared to short-fiber non-woven fabrics, it suppresses the occurrence of non-uniformity and film defects caused by fiber fluffing during casting of a polymer solution. be able to. Furthermore, since the separation membrane is tensioned in the film-forming direction when continuously formed, it is preferable to use a long-fiber nonwoven fabric excellent in dimensional stability as a base material.

  In the long-fiber nonwoven fabric, in terms of moldability and strength, it is preferable that the fibers in the surface layer on the side opposite to the porous support layer have a longitudinal orientation than the fibers in the surface layer on the porous support layer side. According to such a structure, not only a high effect of preventing membrane breakage by maintaining strength is realized, but also a laminate comprising a porous support layer and a substrate when imparting irregularities to the separation membrane The moldability is improved, and the uneven shape on the surface of the separation membrane is stabilized, which is preferable.

  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 ° or more and 25 ° or less, and the fiber orientation in the surface layer on the porous support layer side. The degree of orientation difference with respect to the degree is preferably 10 ° or more and 90 ° or less.

  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. In the nonwoven fabric, when the difference between the fiber orientation degree on the surface layer opposite to the porous support layer and the fiber orientation degree on the porous support layer side surface layer is 10 ° or more and 90 ° or less, the change in the width direction due to heat is suppressed. Can also be preferred.

  Here, the fiber orientation degree is an index indicating the direction of the fibers of the nonwoven fabric substrate constituting the porous support layer. Specifically, the fiber orientation degree is an average value of angles between the film forming direction when continuous film forming is performed, that is, the longitudinal direction of the nonwoven fabric base material and the longitudinal direction of the fibers constituting the nonwoven fabric base material. 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 degree of fiber orientation is measured as follows. First, 10 small piece 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 fibers are selected for each sample, and the angle of the fibers in the longitudinal direction when the longitudinal direction of the nonwoven fabric is 0 ° is measured. Here, the longitudinal direction of the nonwoven fabric refers to “Machine direction” at the time of manufacturing the nonwoven fabric. The longitudinal direction of the nonwoven fabric coincides with the film forming direction of the porous support layer and the MD direction in the figure. The CD direction in the figure corresponds to “Cross direction” at the time of manufacturing the nonwoven fabric.

  In this way, the angle is measured for a total of 100 fibers per nonwoven fabric. For the 100 fibers thus measured, an average value is calculated from the angle in the longitudinal direction. The value obtained by rounding off the first decimal place of the obtained average value is the fiber orientation degree.

  As for the thickness of the substrate, the total thickness of the substrate and the porous support layer is preferably in the range of 30 μm to 300 μm, or in the range of 50 μm to 250 μm.

(1-3) Permeation side channel material <Overview>
On the permeate side surface of the separation membrane main body, the flow path material is fixed to the base material (separation membrane main body) so as to form a permeation side flow path (groove) between adjacent flow path materials. “Provided to form a flow path on the permeate side” means that the permeated fluid that has permeated through the main body of the separation membrane can reach the water collecting pipe when the separation membrane is incorporated in a separation membrane element described later. It means that the road material is formed. Details of the configuration of the channel material are as follows.

<Constituent components of channel material>
The channel material 31 is preferably formed of a material different from that of the separation membrane body 2. The different material means a material having a composition different from that of the material used in the separation membrane body 2. In particular, the composition of the flow path member 31 is preferably different from the composition of the surface of the separation membrane body 2 on which the flow path material 31 is formed, and is different from the composition of any layer forming the separation membrane body 2. It is preferable.

  The material constituting the channel material is not limited to a specific substance, but a resin is preferably used. Specifically, in view of chemical resistance, ethylene vinyl acetate copolymer resin, polyolefin such as polyethylene and polypropylene, and polyolefin copolymer are preferable. In addition, as a material of the flow path material, urethane resin, epoxy resin, polyethersulfone, polyacrylonitrile, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polystyrene, styrene-acrylonitrile copolymer, Styrene-butadiene-acrylonitrile copolymer, polyacetal, polymethyl methacrylate, methacryl-styrene copolymer, cellulose acetate, polycarbonate, polyethylene terephthalate, polybutadiene terephthalate and fluororesin (ethylene trifluoride chloride, polyvinylidene fluoride, tetrafluoroethylene) , Tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkoxyethylene copolymer, tetrafluoroethylene-ethylene copolymer, etc.) Any polymer can also be selected. These materials are used alone or as a mixture of two or more. In particular, since a thermoplastic resin is easy to mold, a channel material having a uniform shape can be formed.

  A composite material is also applicable as the material of the flow path material. Examples of the composite material include a material containing the above-described resin as a base material and further containing a filler. The compression elastic modulus of the channel material can be increased by adding a filler such as a porous inorganic material to the base material. Specifically, alkaline earth metal silicates such as sodium silicate, calcium silicate and magnesium silicate, metal oxides such as silica, alumina and titanium oxide, and alkaline earth metals such as calcium carbonate and magnesium carbonate. Carbonate, pure meteorite, meteorite powder, caustic clay, wollastonite, sepiolite, attapulgite, kaolin, clay, bentonite, gypsum, talc, etc. can be used as fillers. In addition, the addition amount of a filler will not be specifically limited if it is a range which does not impair the effect of this invention.

<Shape and arrangement of channel material>
<< Overview >>
The tricot that has been widely used in the past is knitted and is composed of three-dimensionally intersecting yarns. That is, the tricot has a two-dimensionally continuous structure (planar structure). In such a structure, since the two yarns of the warp and the weft intersect, the usable flow path (particularly the height of the flow path) becomes narrow.

  On the other hand, as an example of the configuration of the present invention, the flow path materials 31 shown in FIG. 1 and the like are arranged so as not to overlap each other. Therefore, the height (that is, the thickness) of the channel material 31 of the present embodiment is all utilized as the height of the channel. Therefore, when the flow path member 31 of the present embodiment is applied, the flow path is higher than when a tricot having the same thickness as the height of the flow path member 31 is applied. That is, since the cross-sectional area of the flow path becomes larger, the flow resistance becomes smaller.

  Moreover, in the form shown in each drawing, a plurality of discontinuous flow path materials 31 are fixed on one separation membrane body 2. “Discontinuous” is a state in which a plurality of flow path members are provided at intervals. That is, when the flow path material 31 in one separation membrane 1 is peeled from the separation membrane body 2, a plurality of flow path materials 31 separated from each other are obtained. On the other hand, members such as nets, tricots, and films exhibit a continuous and integral shape even when separated from the separation membrane body 2.

  By providing a plurality of discontinuous flow path materials 31, the separation membrane 1 can suppress the pressure loss when incorporated into the separation membrane element 100 described later. As an example of such a configuration, in FIG. 2, the channel material 31 is formed discontinuously only in the first direction (the width direction of the separation membrane), and in FIG. 3, the first direction (the width direction of the separation membrane). And in the second direction (the length direction of the separation membrane).

  2 and 3, the permeation-side flow path 5 is formed in the space between the adjacent flow path materials 31. That is, on the permeate side surface of the separation membrane leaf 4 (separation membrane 1), a plurality of flow path materials 31 are provided in the width direction of the separation membrane leaf 4 (separation membrane 1), and two adjacent passage members in the width direction are provided. A permeate-side flow path 5 is defined between the flow path materials 31.

  In the separation membrane element 100 (see FIG. 6) described later, the separation membrane is preferably arranged so that the second direction coincides with the winding direction. That is, in the separation membrane element, the separation membrane has a first direction (width direction of the separation membrane) parallel to the longitudinal direction of the water collection pipe 6 and a second direction (length direction of the separation membrane). 6) is preferably arranged so as to be orthogonal to the longitudinal direction.

  The flow path material 31 is provided discontinuously in the first direction, and in the form shown in FIGS. 2 and 6, the flow path material 31 is provided so as to be continuous from one end to the other end of the separation membrane body 2 in the second direction. When the separation membrane 1 (separation membrane leaf 4) is incorporated in the separation membrane element 100 as shown in FIG. 6, the flow path material 31 continues from the inner end to the outer end of the separation membrane 1 in the winding direction. Are arranged as follows. 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.

  FIG. 6 is an explanatory view schematically showing a separation membrane element 100 in which a separation membrane leaf 4 (separation membrane 1) is wound around the water collecting pipe 6. As shown in FIG. 6 is a developed perspective view showing an embodiment of the separation membrane element. FIG. 6A is a developed perspective view showing a state in which the separation membrane leaf 4 is wound around the water collecting pipe 6, and the separation membrane 1 is described as a surface on one side of the separation membrane leaf 4. FIG. 6B is a perspective view of the completed separation membrane element 100. In the figure, an arrow indicated by CD indicates the longitudinal direction of the water collecting pipe 6 and the width direction of the separation membrane. An arrow indicated by MD indicates the length direction of the separation membrane and the direction of winding around the water collecting pipe 6.

  The phrase “the channel material is continuous in the second direction” mainly means the case where the channel material is provided without interruption as shown in FIG. In addition, as shown in FIG. 3, there are places where the flow path material is interrupted, but even when the flow path material is substantially continuous, the flow path material is included in the form of being continuous in the second direction. In the “substantially continuous” form, preferably, as shown in FIG. 3, the distance e between the flow path members in the second direction (that is, the length of the discontinuous portion in the flow path material) is 5 mm or less. Satisfy that. In particular, the distance e is more preferably 1 mm or less, and further preferably 0.5 mm or less. In addition, the total value of the intervals e included from the beginning to the end of the line of flow path materials arranged in the second direction is preferably 100 mm or less, more preferably 30 mm or less, and more preferably 3 mm or less. Further preferred. In the form of FIG. 2, the interval e is 0 (zero).

  When the flow path material 31 is provided without interruption as shown in FIG. 2, membrane dropping is suppressed during pressure filtration. Membrane sagging is that the membrane falls into the channel and narrows the channel.

  In FIG. 3, the flow path material 31 is discontinuously provided not only in the first direction but also in the second direction (except for the above-described case). That is, the channel material 31 is provided at intervals in the length direction. However, as described above, the passage material 31 is substantially continuous in the second direction, so that the film sagging is suppressed. In addition, by providing the discontinuous flow path material 31 in the two directions as described above, the contact area between the flow path material and the fluid is reduced, so that an effect that the pressure loss is reduced is obtained. In other words, this form is a configuration in which the flow path 5 includes a branch point. That is, in the configuration of FIG. 3, the permeating fluid is divided by the flow path material 31 while flowing through the flow path 5, and can further merge downstream.

  As described above, in FIG. 2, the flow path material 31 is provided so as to continue from one end to the other end of the separation membrane body 2 in the second direction. In FIG. 3, the flow path material 31 is divided into a plurality of portions in the second direction, but these plurality of portions are provided so as to be arranged from one end to the other end of the separation membrane body 2.

  The channel material is “provided from one end to the other end of the separation membrane body” means that the channel material is provided up to the edge of the separation membrane body 2 and the channel material is provided in the vicinity of the edge. Includes both forms with no areas. That is, the flow path material only needs to be distributed in the second direction to such an extent that a flow path on the permeation side can be formed, and there may be a portion where the flow path material is not provided in the separation membrane body. For example, in the surface on the permeate side, a flow path material does not need to be provided in a portion (in other words, a contact portion) bonded to another separation membrane. Moreover, the area | region where a flow-path material is not arrange | positioned may be provided in some places, such as the edge part of a separation membrane, for the reason on the other specification or manufacture.

  Also in the first direction, the channel material 31 can be distributed substantially evenly over the entire separation membrane body. However, similarly to the distribution in the second direction, it is not necessary to provide the flow path material at the bonding portion with the other separation membrane on the permeate side surface. Moreover, the area | region where a flow-path material is not arrange | positioned may be provided in some places, such as the edge part of a separation membrane, for the reason on the other specification or manufacture.

<< Dimensions of separation membrane body and flow path material >>
2 to 4, a to f indicate the following values.
a: Length of the separation membrane body 2 b: Spacing of the flow path material 31 in the width direction of the separation membrane body 2 c: Height of the flow path material (the flow path material 31 and the permeation side surface 22 of the separation membrane body 2 Difference in height)
d: width of the channel material 31 e: interval of the channel material in the length direction of the separation membrane body 2 f: length of the channel material 31

  For measurement of the values a, b, c, d, e, and f, for example, a commercially available shape measurement system or a microscope can be used. Each value is obtained by performing measurement at 30 or more locations on one separation membrane, and calculating an average value by dividing the sum of these values by the number of measurement total locations. Thus, each value obtained as a result of the measurement at at least 30 locations should satisfy the range described below. Moreover, the dimension of the flow path material may be different depending on the separation membrane leaf.

(Length of separation membrane body a)
The length a is a distance from one end of the separation membrane body 2 to the other end in the second direction (length direction of the separation membrane). When this distance is not constant, the length a can be obtained by measuring this distance at 30 or more positions in one separation membrane body 2 and obtaining an average value.

(Flow path width b in the first direction)
The interval b between the adjacent flow path members 31 in the first direction (the width direction of the separation membrane) corresponds to the width of the flow path 5. When the width of one flow path 5 is not constant in one cross section, that is, when the side surfaces of two adjacent flow path materials 31 are not parallel, the maximum value of the width of one flow path 5 within one cross section The average value of the minimum values is measured, and the average value is calculated. As shown in FIG. 4, in the cross section perpendicular to the second direction, when the channel material 31 has a trapezoidal shape with a thin top and a thick bottom, first, the distance between the upper parts of the two adjacent channel materials 31 and the lower part The distance between them is measured and the average value is calculated. The distance between the flow path materials 31 is measured at any 30 or more cross sections, and the average value is calculated for each cross section. And the space | interval b is calculated by calculating further the arithmetic mean value of the average value obtained in this way.

  As the distance b increases, the pressure loss decreases, but the film falls easily. Conversely, the smaller the distance b, the less likely the film will drop, but the greater the pressure loss. In particular, when operating at a high pressure exceeding 1.5 MPa, the salt concentration of the feed water is often high and the concentration polarization is large on the membrane surface, which may increase the permeation resistance. In such a case, if the flow channel on the permeate side is simply enlarged and the pressure loss is reduced to increase the permeation efficiency too much, concentration polarization tends to be accelerated, and the membrane falls into the permeate side flow channel, causing the permeate side flow. The road shrinks. For this reason, the interval b is preferably 0.02 mm or more and 5 mm or less, and within this range, the pressure loss can be reduced while suppressing film sagging. The distance b is more preferably 0.05 mm or more and 3 mm or less, 0.2 mm or more and 2 mm or less, and further preferably 0.3 mm or more and 0.8 mm or less.

(Permeate side channel material height)
The permeation side channel material height c is the difference in height between the channel material and the surface of the separation membrane body. As shown in FIG. 4, the height c is a difference in height between the highest portion of the flow path material 31 and the permeate side surface of the separation membrane main body in a cross section perpendicular to the second direction. That is, in the height, the thickness of the portion impregnated in the base material is not considered.

  The height c is a value obtained by measuring the heights of the flow path materials 31 at 30 or more locations and averaging them. The height c of the flow path material may be obtained by observing a cross section of the flow path material in the same plane, or may be obtained by observing cross sections of the flow path material in a plurality of planes.

  The height c can be appropriately selected according to the use condition and purpose of the element, but may be set as follows, for example.

  The larger the height c, the smaller the flow resistance. Therefore, the height c is preferably 0.01 mm or more. On the other hand, the smaller the height c, the larger the number of films filled per element. Therefore, the height c is preferably 0.6 mm or less. More preferably, it is 0.1 mm or more and 0.5 mm or less.

(Width d of the channel material)
The width d of the channel material 31 is preferably 0.1 mm or more. By being 0.1 mm or more, even when pressure is applied to the flow path material 31 during operation of the separation membrane element, the shape of the flow path material can be maintained and the permeate side flow path is stably formed. The width d is preferably 2.0 mm or less. When the width d is 2.0 mm or less, a sufficient flow path on the permeation side can be secured. More preferably, it is 0.2 mm or more and 1.0 mm or less.

  When the width of the channel material is wider than the channel width b in the first direction, the pressure applied to the channel material can be dispersed.

  The width d of the channel material 31 is measured as follows. First, in one cross section perpendicular to the first direction (the width direction of the separation membrane), an average value of the maximum width and the minimum width of one flow path material 31 is calculated. That is, in the channel material 31 with a thin upper part and a thick lower part as shown in FIG. 4, the width of the lower part and the upper part of the channel material are measured, and the average value is calculated. By calculating such an average value in at least 30 cross-sections and calculating the arithmetic average thereof, the width d per film can be calculated.

  The channel material 31 is formed such that its length is larger than its width. Such a long channel material 31 is also referred to as a “wall-like object”.

(Channel material interval e in the second direction)
The interval e between the flow path members 31 in the second direction is the shortest distance between the flow path members 31 adjacent in the second direction (the length direction of the separation membrane). As shown in FIG. 2, the flow path material 31 is provided continuously from one end to the other end of the separation membrane body 2 in the second direction (in the separation membrane element, from the inner end to the outer end in the winding direction). If it is, the interval e is 0 mm. Further, as shown in FIG. 3, when the flow path material 31 is interrupted in the second direction, the interval e is preferably 5 mm or less, more preferably 1 mm or less, and further preferably 0.5 mm or less. is there. When the distance e is within the above range, the mechanical load on the film is small even when the film is dropped, and the pressure loss due to the blockage of the flow path can be relatively small. In addition, the minimum of the space | interval e is 0 mm.

(Length f of channel material)
The length f of the flow path material 31 is the length of the flow path material 31 in the length direction of the separation membrane body 2 (that is, the second direction). The length f is obtained by measuring the length of 30 or more flow path members 31 in one separation membrane 1 and calculating the average value. The length f of the channel material may be equal to or less than the length a of the separation membrane body. When the length f of the flow path material is equal to the length a of the separation membrane body, the flow path material 31 is continuously provided from the inner end to the outer end in the winding direction of the separation membrane 1. Point to. The length f is preferably 10 mm or more, more preferably 20 mm or more. Since the length f is 10 mm or more, the flow path is secured even under pressure.

(shape)
The shape of the channel material is not particularly limited, but a shape that reduces the flow resistance of the channel and stabilizes the channel when permeated can be selected. In these respects, in any cross section perpendicular to the surface direction of the separation membrane, the shape of the flow path material may be a straight column shape, a trapezoidal shape, a curved column shape, or a combination thereof.

  When the cross-sectional shape of the channel material is trapezoidal, if the difference between the length of the upper base and the length of the lower base in the first direction is too large, membrane drop during pressure filtration tends to occur at the membrane that contacts the smaller one Become. For example, when the upper base of the channel material is shorter than the lower base, the upper width of the channel between them is wider than the lower width. Therefore, the upper film tends to drop downward. Therefore, in order to suppress such a drop, the ratio of the length of the upper base to the length of the lower base of the flow path material is preferably 0.6 or more and 1.4 or less, and is 0.8 or more and 1.2 or less. Further preferred.

  The shape of the channel material is preferably a straight column shape perpendicular to the separation membrane surface described later from the viewpoint of reducing flow resistance. Further, the channel material may be formed so that the width becomes smaller at a higher location, or conversely, the channel material may be formed so that the width becomes wider at a higher location, or the height from the surface of the separation membrane. Regardless, it may be formed to have the same width.

  However, the upper side of the cross-section of the flow path material may be rounded as long as the flow path material is not significantly crushed during pressure filtration.

  The channel material can be formed of a thermoplastic resin. If the flow path material is a thermoplastic resin, the shape of the flow path material can be freely changed to satisfy the required separation characteristics and permeation performance conditions by changing the processing temperature and the type of thermoplastic resin to be selected. Can be adjusted.

  Further, the shape of the separation membrane of the flow path material in the planar direction may be linear as a whole as shown in FIGS. 2 and 3, and other shapes are, for example, curved, sawtooth, and wavy. There may be. In these shapes, the channel material may be a broken line or a dot. From the viewpoint of reducing the flow resistance, a dot shape or a broken line shape is preferable. However, since the flow path material is interrupted, the number of places where film sagging occurs during pressure filtration increases.

  Further, when the shape of the separation membrane of the flow path material in the planar direction is a straight line, the adjacent flow path materials may be arranged substantially parallel to each other. “Arranged substantially in parallel” means, for example, that the channel material does not intersect on the separation membrane, the angle formed by the longitudinal direction of two adjacent channel materials is 0 ° or more and 30 ° or less, It includes that the angle is from 0 ° to 15 °, and that the angle is from 0 ° to 5 °.

  Further, the angle formed by the longitudinal direction of the flow path material and the longitudinal direction of the water collecting pipe is preferably 60 ° or more and 120 ° or less, more preferably 75 ° or more and 105 ° or less, and 85 ° or more and 95 °. More preferably, it is as follows. When the angle formed by the longitudinal direction of the flow path 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 stably form the flow path, it is preferable that the separation membrane body can be prevented from dropping when the separation membrane body is pressurized in the separation membrane element. For this purpose, it is preferable that the contact area between the separation membrane main body and the flow path material is large, that is, the area of the flow path material relative to the area of the separation membrane main body (projected area on the membrane surface of the separation membrane main body) is large. On the other hand, in order to reduce pressure loss, it is preferable that the cross-sectional area of a flow path is wide. The cross section of the flow path is to secure a large contact area between the separation membrane body perpendicular to the longitudinal direction of the flow path and the flow path material and to ensure a wide cross sectional area of the flow path. The cross-sectional shape is preferably a concave lens shape. Further, the flow path member 31 may have a straight column shape having no change in width in a cross-sectional shape in a direction perpendicular to the winding direction. Moreover, as long as the separation membrane performance is not affected, the cross-sectional shape in the direction perpendicular to the winding direction has a trapezoidal wall-like object having a change in width, an elliptic cylinder, an elliptic cone, four A shape like a pyramid or a hemisphere may be sufficient.

  The shape of the flow path material is not limited to the shape shown in FIGS. Change the processing temperature and the type of hot-melt resin to be selected when the flow path material is placed on the permeate side surface of the separation membrane body by, for example, a hot melt method by fixing a molten material. Thus, the shape of the flow path material can be freely adjusted so that the required separation characteristics and permeation performance conditions can be satisfied.

  1 to 3, the planar shape of the flow path member 31 is linear in the length direction. However, the flow path member 31 can be changed to another shape as long as it is convex with respect to the surface of the separation membrane body 2 and does not impair the desired effect as the separation membrane element. That is, the shape of the flow path material in the plane direction may be a curved line, a wavy line, or the like. A plurality of flow path materials included in one separation membrane may be formed so that at least one of width and length is different from each other.

(Projected area ratio)
The projected area ratio of the flow path material to the permeation side surface of the separation membrane is 0.03 or more and 0.85 or less, particularly in terms of reducing the flow resistance of the permeation side flow path and forming the flow path stably. Is preferably 0.15 or more and 0.85 or less, more preferably 0.2 or more and 0.75 or less, and further preferably 0.3 or more and 0.6 or less. The projected area ratio is a value obtained by dividing the projected area of the flow path material obtained when the separation membrane is cut out at 5 cm × 5 cm and projected onto a plane parallel to the surface direction of the separation membrane by the cut-out area (25 cm ² ). It is. This value can also be expressed by the formula of df / (b + d) (e + f) according to b described above.

(Defect rate)
The water that has permeated through the separation membrane passes through the permeation side flow path 5 and is collected in the water collecting pipe 6. In the separation membrane, water that has permeated through a region far from the water collecting pipe, that is, a region near the outer end in the winding direction (a region near the right end in FIG. 6A), In the turning direction, it merges with the water that has passed through the inner region, and heads toward the water collecting pipe 6. Therefore, in the permeate side flow path, the amount of water present is smaller in the direction far from the water collecting pipe 6.

  For this reason, there is no permeation-side channel material in the region near the end on the outer side in the winding direction, and even if the flow resistance in that region is high, the influence on the amount of water produced by the entire element is slight. For the same reason, the formation accuracy of the flow path material is low in the region near the end on the outer side in the winding direction, and the resin forming the flow path material is continuously applied in the first direction (the width direction of the separation membrane). However, the effect on the amount of water produced as an element is small. In this region, the same applies to the case where the separation membrane body is applied without a gap in the surface direction (xy plane).

  Therefore, the distance from the outer end in the winding direction of the separation membrane main body 2 to the outer end in the winding direction of the permeate-side flow path member 31, that is, the outer end in the winding direction of the separation membrane main body 2 is provided. The length L3 in the second direction (length direction of the separation membrane) of the region R3, which is a region where the permeation-side flow path is not formed, is the length L1 in the second direction of the entire separation membrane ( It corresponds to the above-mentioned “a”.) The ratio of occupying with respect to “a” is preferably from 0% to 30%, more preferably from 0% to 10%, particularly preferably from 0% to 3%. This ratio is called a defect ratio.

  The defect rate is represented by (L3 / L1) × 100 in FIG.

  For convenience of explanation, FIG. 7 shows a mode in which the permeation-side channel material is not provided in the region R3. However, the region 3 may be a region provided with a permeate-side flow path material continuous in the width direction.

  FIG. 7 is a cross-sectional view of the separation membrane body 2 and the outer end of the permeate side flow path member 31 in the winding direction cut in the length direction of the permeate side flow path member 31. In FIG. 7, the permeate-side channel material 31 is fixed to the separation membrane main body 2 and extends to the front of the outer end in the winding direction of the separation membrane main body 2. For convenience of explanation, FIG. 7 shows a mode in which the permeate-side flow path material 31 is continuously provided in the length direction, but the various forms described above are applied as the permeate-side flow path material 31. Is as already described.

  In the drawing, a region where the permeate side channel material 31 is provided is indicated by R2, and a region where the permeate side channel material 31 is not provided is indicated by R3. Further, the length of the separation membrane body 2 in the MD direction is L1, the length of the permeation side flow path material 31 in the MD direction (that is, the length of the region R2) is L2, and the MD of the region R3 where the permeation side flow path material 31 is not present. The length in the direction is indicated by L3. Here, the MD direction represents the length direction of the separation membrane and the winding direction of the separation membrane.

[2. Separation membrane element)
(2-1) Overview As shown in FIG. 6, the separation membrane element 100 includes the water collecting pipe 6 and any one of the above-described configurations, and a plurality of separation membrane leaves 4 wound around the water collecting pipe 6 ( A separation membrane 1) is provided. A plurality of separation membrane leaves 4 are wound in a laminated state, and the lamination direction L of the separation membrane leaves 4 is equal to the radial direction of the separation membrane element 100.

  As shown in FIG. 1, the separation membrane 1 forms a separation membrane leaf 4 (sometimes referred to as “leaf” or “membrane leaf”). In the separation membrane leaf 4, the separation membrane 1 is arranged so that the supply-side surface 21 faces the supply-side surface 71 of another separation membrane 7 with a supply-side flow path material (not shown) interposed therebetween. In the separation membrane leaf 4, a supply-side flow path is formed between the supply-side surfaces of the separation membranes facing each other.

  Further, the separation membrane 1 and the separation membrane 7 of the other separation membrane leaf facing the permeation-side surface 22 of the separation membrane 1 form an envelope-like membrane by overlapping the two separation membrane leaves 4. . In the envelope-like membrane, between the opposite permeate side surfaces, in the rectangular shape of the separation membrane, only one side inside the winding direction is opened, and the other three sides are sealed so that the permeate flows into the water collecting pipe 6. Stopped. The permeate is isolated from the raw water by this envelope membrane.

  As a result of intensive studies, the present inventors have found that the separation membrane element can be easily wound and the performance of the separation membrane element can be sufficiently improved by configuring the separation membrane element as follows. The details of the configuration of the separation membrane element are as follows.

  It is preferable that the position of the bottom of the separation membrane leaf (separation membrane) in the width direction does not match between the flow passage material of one separation membrane leaf (separation membrane) and the flow passage material of another separation membrane leaf (separation membrane). That is, the position of the bottom of the flow path material of one separation membrane leaf (separation membrane) and the position of the bottom of the flow path material of at least one other separation membrane leaf (separation membrane) are shifted in the width direction. Yes.

  Since the rigidity of the separation membrane is higher in the portion where the flow path material is fixed to the separation membrane than the portion where the flow path material is not fixed, the rigidity of the separation membrane to which the flow path material is fixed is likely to be uneven. In this embodiment, the bottom position of the separation membrane leaf width direction of the permeation side channel material fixed to one separation membrane leaf permeation side surface and the permeation side channel material existing in the vertical direction of the other separation membrane leaf is It does not match. That is, the position of the bottom of the flow path material of one separation membrane leaf (separation membrane) and the position of the bottom of the flow path material of at least one other separation membrane leaf (separation membrane) are shifted in the width direction. Yes. According to this structure, since the rigidity of the whole several separation membrane wound around the water collection pipe | tube becomes uniform, it becomes easy to wind a separation membrane element. As a result, the separation membrane leaves are bonded to each other (particularly, the surfaces on the transmission side in the case of forming an envelope-shaped membrane to be described later), and the spread of the adhesive can be suppressed to make the adhesive thickness uniform. Further, the element can be wound stably while suppressing damage to the surface of the separation membrane.

  By suppressing the spread of the adhesive, a sufficient effective membrane area can be obtained. Further, by making the adhesive thickness uniform, even when the operation is repeated, the separation membrane body and the adhesive are hardly peeled off at the adhesion portion between the separation membrane permeation sides, and the performance degradation of the separation membrane element can be suppressed.

  Further, when the permeation side channel material is provided on both of the opposing separation membrane permeation side surfaces, the permeation side channel material fixed on the separation membrane leaf permeation side surface is adjacent to the separation membrane leaf in the vertical direction. Since the base positions of the permeation side flow path materials in the separation membrane leaf width direction do not match, the contact area between the permeation side flow path materials decreases, and friction between the permeation side flow path materials during element winding decreases. Therefore, peeling and destruction of the permeation side channel material can be suppressed. Further, the separation membrane element can be easily wound, and the spread of the adhesive for adhering the separation membrane leaves can be suppressed to make the adhesive thickness uniform.

  On the other hand, if the bottom side position in the separation membrane leaf width direction of the permeation side channel material fixed to the surface of the separation membrane leaf permeation and the permeation side channel material existing in the vertical direction of the separation membrane leaf match, Since the rigidity of the whole of the plurality of separation membranes wound around is uneven, the spread of the adhesive and the variation of the adhesive thickness occur when the separation membrane element is wound.

  “The bottom position of the permeation side channel material in the separation membrane leaf width direction (separation membrane width direction)” refers to a plane perpendicular to the separation membrane leaf membrane surface and parallel to the width direction, as shown in FIG. In the cross section, the center g of the bottom side where the permeate-side channel material is fixed to the separation membrane is shown.

  “The bottom position in the separation membrane leaf width direction (separation membrane width direction) does not match” means that, as shown in FIG. 5 (a), in a cross section with respect to a plane perpendicular to the separation membrane leaf film surface and parallel to the width direction. It shows that the bottom side position of the permeation side channel material existing in the vertical direction of the separation membrane leaf includes one or more that are not on the same line as the straight line h perpendicular to the bottom side. The straight line h is defined as a straight line passing through the bottom side position of the permeate-side channel material fixed to the separation membrane present on the most water collection tube side among the separation membrane leaves stacked around the water collection tube. In other words, at least one other separation membrane leaf (separation membrane) stacked outside the separation membrane leaf with respect to the bottom side position of the flow path material of the separation membrane leaf (separation membrane) existing on the most water collecting pipe side The position of the bottom of the channel material is shifted in the width direction of the separation membrane leaf (separation membrane).

  The bottom position of the separation membrane leaf width direction of the permeation side channel material fixed to the surface of the separation membrane leaf permeation side can be adjusted by changing the permeation side channel material arrangement according to each laminated separation membrane leaf. is there. The permeation-side channel material arrangement can be adjusted by changing the shape of the gravure roll to be used or by changing the resin and amount to be configured. Moreover, when providing the permeation | transmission side channel material by a hot-melt method, it can also adjust by changing process temperature and the discharge pressure of resin.

  Further, in the step of laminating the separation membrane leaf, it can also be achieved by shifting one separation membrane leaf and another separation membrane leaf laminated on the one separation membrane leaf by a certain distance in the separation membrane leaf width direction. .

  Further, the separation membrane leaf width of the permeation side channel material fixed to the permeation side surface of one separation membrane leaf and the permeation side channel material fixed to another separation membrane leaf adjacent to the one separation membrane leaf The distance of the base position in the direction is preferably 0.01 mm to 2.5 mm in the separation membrane width direction.

  A permeation side flow path material fixed to the permeation side surface of one separation membrane leaf and a permeation side flow path material fixed to another separation membrane leaf adjacent to the one separation membrane leaf in the separation membrane leaf width direction. When the distance of the base position is within the above range, the rigidity of the whole of the plurality of separation membranes wound around the water collecting pipe is made uniform, so that the separation membrane element is easily wound. As a result, the spread of the adhesive that bonds the separation membrane leaves can be suppressed, and the adhesive thickness can be made uniform. Moreover, it can implement stably, suppressing the damage | wound to the separation membrane surface.

  Further, when the separation membrane element is wound, particularly in the tightening step, the force applied to the permeation side flow path material is reduced, and the element can be stably wound while preventing the permeation side flow path material from being broken or peeled off.

  On the other hand, the separation membrane of the permeation side flow path material fixed to the permeation side surface of one separation membrane leaf and the permeation side flow path material fixed to another separation membrane leaf adjacent to the one separation membrane leaf If the distance between the bottom positions in the leaf width direction is too large, the permeation side flow path is blocked by the adhesive between the separation membrane permeation sides, and the effective membrane area is reduced.

  “Permeation side channel material fixed to the permeation side surface of one separation membrane leaf and permeation side channel material fixed to another separation membrane leaf adjacent to the one separation membrane leaf As shown in FIG. 5 (b), the distance between the bottom position of the separation membrane leaf width direction in the cross section with respect to a plane perpendicular to the separation membrane leaf film surface and parallel to the width direction, This is the distance i in the width direction of the separation membrane leaf from the permeation side flow channel material closest to the width direction among the permeation side flow channel materials fixed to the other separation membrane leaf adjacent to one separation membrane leaf.

  Furthermore, it is preferable that the angle formed by the inner edge of one separation membrane leaf and the inner edge of another separation membrane leaf adjacent to the one separation membrane leaf is 0 degree or more and 20 degrees or less.

  The angle formed by the inner edge of one separation membrane leaf and the inner edge of another separation membrane leaf adjacent to the one separation membrane leaf is within the above range, so that it is wound around the water collecting pipe. Since the rigidity of the plurality of rotated separation membranes becomes uniform, the separation membrane element can be easily wound. As a result, the spread of the adhesive that bonds the separation membrane leaves can be suppressed, and the adhesive thickness can be made uniform. Further, the element can be wound stably while suppressing damage to the surface of the separation membrane.

  On the other hand, if the angle formed between the inner edge of one separation membrane leaf and the inner edge of another separation membrane leaf adjacent to the one separation membrane leaf is too large, the permeated water will flow from the permeate side flow path. The efficiency collected in the water collecting pipe deteriorates, leading to a decrease in the performance of the separation membrane element.

  “An angle formed by the inner edge of one separation membrane leaf and the inner edge of another separation membrane leaf adjacent to the one separation membrane leaf” as shown in FIG. About the water collecting pipe side end in the separation membrane leaf width direction of the disassembled separation membrane element, an acute angle j among the angles formed between adjacent separation membrane leaves. The average value of all adjacent separation membrane leaves was calculated to calculate the angle.

  The angle formed between the inner edge of one separation membrane leaf and the inner edge of another separation membrane leaf adjacent to the one separation membrane leaf changes the arrangement of the permeate-side channel material depending on the separation membrane leaf. It can be adjusted by doing. The permeation-side channel material arrangement can be adjusted by changing the shape of the gravure roll to be used or by changing the resin and amount to be configured. Moreover, when providing the permeation | transmission side channel material by a hot-melt method, it can also adjust by changing process temperature and the discharge pressure of resin.

  Further, in the step of laminating the separation membrane leaves, it can also be achieved by providing a certain angle between one separation membrane leaf and another separation membrane leaf to be laminated on the one separation membrane leaf.

  In other words, the permeation side flow path material fixed to the permeation side surface of one separation membrane leaf and the permeation side flow path material fixed to another separation membrane leaf adjacent to the one separation membrane leaf are separated from each other. There is a case where a certain angle is formed with the angle formed by the above, and a case where the permeation side flow path materials do not form an angle depending on the separation membrane leaf.

(2-2) Separation membrane <Overview>
The separation membrane 1 is wound around the water collecting pipe 6 and is arranged so that the width direction of the separation membrane is along the longitudinal direction of the water collecting pipe 6. As a result, the separation membrane 1 is disposed such that the length direction is along the winding direction.

  Therefore, the channel material 31 that is a wall-like material is discontinuously arranged at least in the longitudinal direction of the water collecting pipe 6 on the permeation side surface 22 of the separation membrane 1. That is, the flow path 5 is formed to be continuous from the outer end to the inner end of the separation membrane in the winding direction. As a result, the permeated water can easily reach the central pipe, that is, the flow resistance is reduced, so that a large amount of fresh water is obtained.

The “inner side in the winding direction” and “outer side in the winding direction” are as shown in FIG. That is, the “inner end portion in the winding direction” and the “outer end portion in the winding direction” correspond to the end portion closer to the water collecting pipe 6 and the far end portion in the separation membrane 1, respectively.
As described above, since the flow path material does not have to reach the edge of the separation membrane, for example, at the outer end of the envelope membrane in the winding direction and the end of the envelope membrane in the longitudinal direction of the water collecting pipe, The channel material may not be provided.

<Separation membrane leaf and envelope membrane>
As shown in FIG. 1, the separation membrane forms a separation membrane leaf 4 (also referred to as “leaf” or “membrane leaf”). In the separation membrane leaf 4, the separation membrane 1 is arranged so that the supply-side surface 21 faces the supply-side surface 71 of another separation membrane 7 with a supply-side flow path material (not shown) interposed therebetween. In the separation membrane leaf 4, a supply-side flow path is formed between the supply-side surfaces of the separation membranes facing each other.

  Further, the separation membrane 1 and the separation membrane 7 of the other separation membrane leaf facing the permeation-side surface 22 of the separation membrane 1 form an envelope-like membrane by overlapping the two separation membrane leaves 4. . In the envelope-like membrane, between the opposite permeate side surfaces, in the rectangular shape of the separation membrane, only one side inside the winding direction is opened, and the other three sides are sealed so that the permeate flows into the water collecting pipe 6. Stopped. The permeate is isolated from the raw water by this envelope membrane.

  Examples of the sealing include a form bonded by an adhesive or hot melt, 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.

  In addition, on the surface on the supply side of the separation membrane, the inner end in the winding direction is closed by folding or sealing. Since the surface on the supply side of the separation membrane is sealed rather than being folded, bending at the end of the separation membrane is unlikely to occur. By suppressing the occurrence of bending in the vicinity of the crease, the generation of voids between the separation membranes and the occurrence of leaks due to the voids are suppressed when wound.

  By suppressing the occurrence of leak in this way, the recovery rate of the envelope film is improved. The recovery rate of the envelope-like film is obtained as follows. That is, an air leak test (air leak test) of the separation membrane element is performed in water, and the number of envelope-shaped membranes in which the leak has occurred is counted. Based on the count result, the ratio of (number of envelope films in which air leak has occurred / number of envelope films used for evaluation) is calculated as the recovery rate of the envelope film.

  A specific air leak test method is as follows. The end of the central pipe of the separation membrane element is sealed, and air is injected from the other end. The injected air passes through the holes of the water collecting pipe and reaches the permeation side of the separation membrane. However, as described above, if the separation membrane is not sufficiently folded and bent near the fold, Will move through the gap. As a result, the air moves to the supply side of the separation membrane, and the air reaches the water from the end (supply side) of the separation membrane element. Thus, air leak can be confirmed as the generation of bubbles.

  When the separation membrane leaf is formed by folding, the longer the separation membrane leaf (that is, the longer the original separation membrane), the longer the time required for folding the separation membrane. However, sealing the supply side surface of the separation membrane instead of folding it can suppress an increase in manufacturing time even if the separation membrane leaf is long.

  In the separation membrane leaf and the envelope membrane, the separation membranes facing each other (separation membranes 1 and 7 in FIG. 1) may have the same configuration or different configurations. That is, in the separation membrane element, at least one of the two permeate-side surfaces facing each other only needs to be provided with the above-described permeation-side flow path material, and therefore the separation membrane element does not include the permeation-side flow path material. Separation membranes may be alternately stacked. However, for convenience of explanation, in the separation membrane element and the explanation related thereto, the “separation membrane” includes a separation membrane that does not include the permeate-side flow path material (for example, a membrane that has the same configuration as the separation membrane main body).

  The separation membranes facing each other on the permeate side surface or the supply side surface may be two different separation membranes, or one membrane folded.

(2-3) Permeation-side flow path As described above, the separation membrane 1 includes the permeation-side flow path material 31. By the permeation side flow path member 31, a permeation side flow path is formed inside the envelope-shaped membrane, that is, between the permeation side surfaces of the facing separation membranes.

(2-4) Supply side channel (channel material)
The separation membrane element 100 includes a channel material (not shown) having a projected area ratio with respect to the separation membrane 1 exceeding 0 and less than 1 between the surfaces on the supply side of the facing separation membrane. The projected area ratio of the supply-side channel material is preferably 0.03 or more and 0.50 or less, more preferably 0.10 or more and 0.40 or less, and particularly preferably 0.15 or more and 0.35 or less. . When the projected area ratio is 0.03 or more and 0.50 or less, the flow resistance can be suppressed to be relatively small. The projected area ratio refers to the projected area obtained when the separation membrane and the supply-side channel material are cut out at 5 cm × 5 cm, and the supply-side channel material is projected onto a plane parallel to the surface direction of the separation membrane. Divided value.

  As will be described later, the height of the supply-side channel material is preferably more than 0.5 mm and not more than 2.0 mm, more preferably not less than 0.6 mm and not more than 1.0 mm, in consideration of the balance of each performance and operation cost.

  The shape of the supply-side channel material is not particularly limited, and may have a continuous shape or a discontinuous shape. Examples of the channel material having a continuous shape include members such as a film and a net. Here, the continuous shape means that it is continuous over the entire range of the flow path material. The continuous shape may include a portion where a part of the flow path material is discontinuous to such an extent that a problem such as a decrease in the amount of water produced does not occur. The definition of “discontinuity” is as described for the passage-side channel material. 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.

(Unevenness processing)
Further, instead of disposing the supply-side channel material on the supply-side surface of the separation membrane, a difference in height can be imparted to the supply side of the separation membrane by a method such as embossing, hydraulic forming, or calendering.

  Examples of the embossing method include roll embossing, and the pressure and processing temperature for carrying out this can be appropriately determined according to the melting point of the separation membrane. For example, when the separation membrane has a porous support layer containing an epoxy resin, the linear pressure is preferably 10 kg / cm or more and 60 kg / cm or less, and the heating temperature is preferably 40 ° C. or more and 150 ° C. or less. Moreover, when it has a porous support layer containing heat resistant resins, such as polysulfone, it is preferable that it is 10 to 70 kg / cm of linear pressure, and roll heating temperature 70 to 160 degreeC is preferable. In any case of roll embossing, a winding speed of 1 m / min to 20 m / min is preferable.

  When embossing is performed, the shape of the roll handle is not particularly limited, but it is important to reduce the flow resistance of the flow path and stabilize the flow path when supplying and permeating fluid to the separation membrane element. is there. In these respects, there are ellipses, circles, ellipses, trapezoids, triangles, rectangles, squares, parallelograms, rhombuses, and irregular shapes in the shape observed from the upper surface. Those formed in the surface direction, those formed in a widened form, and those formed in a narrowed form are used.

  The difference in height on the supply-side surface of the separation membrane that can be imparted by embossing can be freely adjusted by changing the pressure heat treatment conditions so as to satisfy the conditions that require separation characteristics and water permeation performance. However, if the height difference on the supply side surface of the separation membrane is too deep, the flow resistance becomes small, but the number of separation membrane leaves that can be filled in the vessel when it is made into an element decreases. If the height difference is small, the flow resistance of the flow path increases, and the separation characteristics and water permeation performance 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 of each performance and the operating cost described above, in the separation membrane, the difference in height of the supply side surface of the separation membrane is preferably more than 0.5 mm and preferably 2.0 mm or less, and 0.6 mm or more. 1.0 mm or less is more preferable.

  The difference in height on the supply side surface of the separation membrane can be obtained by the same method as in the case of the above-described difference in height on the permeation side of the separation membrane.

  The channel width is preferably 0.2 mm or more and 10 mm or less, and more preferably 0.5 mm or more and 3 mm or less.

  The pitch may be appropriately designed between 1/10 and 50 times the channel width. The flow path width is the part that sinks on the surface where the height difference exists, and the pitch is the highest point on the surface where the height difference exists to the highest point on the adjacent high part. It is the horizontal distance.

  The projected area ratio of the portion that becomes convex by embossing is preferably 0.03 or more and 0.5 or less, more preferably 0.10 or more and 0.40, for the same reason as in the case of the supply-side channel material. Hereinafter, it is particularly preferably 0.15 or more and 0.35 or less.

  The “height difference” in the surface of the separation membrane is the difference in height between the surface of the separation membrane body and the apex of the flow channel material (that is, the height of the flow channel material). Is the difference in height between the concave and convex portions.

(2-5) Water Collection Pipe The water collection pipe 6 is not particularly limited as long as it is configured so that permeated water flows therethrough. As the water collecting pipe 6, for example, a cylindrical member having a side surface provided with a plurality of holes is used.

[3. Method for manufacturing separation membrane element]
The manufacturing method of a separation membrane element includes the process of manufacturing a separation membrane. In addition, the step of producing the separation membrane includes at least the following steps:
Preparing a separation membrane body having a base material and a separation functional layer;
A step of softening a material having a composition different from that of the separation membrane body by heat,
The softened material is disposed on the base material side surface of the separation membrane main body to form a permeation-side flow path material, and the material is solidified to form the permeation side on the separation membrane main body. A step of fixing the flow path material.

  Each process in the manufacturing method of a separation membrane element is demonstrated below.

(3-1) Manufacture of separation membrane body The manufacturing method of the separation membrane body has been described above, but it is summarized as follows.

  The 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.

  In addition, before or after the chemical treatment, unevenness may be formed on the separation membrane main body by embossing or the like.

(3-2) Arrangement of Permeation Side Channel Material The method for manufacturing a separation membrane includes a step of providing a discontinuous channel material on the permeation side surface of the separation membrane main body. This step may be performed at any time during the manufacture of the separation membrane. For example, the flow path material may be provided before the porous support layer is formed on the base material, or after the porous support layer is provided and before the separation functional layer is formed. It may be performed after the separation functional layer is formed and before or after the above-described chemical treatment is performed.

  The method of arranging the flow path material includes, for example, a step of arranging a soft material on the separation membrane and a step of curing it. Specifically, ultraviolet curable resin, chemical polymerization, hot melt, drying or the like is used for the arrangement of the flow path material. In particular, hot melt is preferably used. Specifically, a step of softening a material such as resin by heat (that is, heat melting), a step of placing the softened material on the separation membrane, and curing the material by cooling. A step of fixing on the separation membrane.

  Examples of the method for arranging the flow path material include coating, printing, spraying, and the like. Examples of the equipment used include a nozzle type hot melt applicator, a spray type hot melt applicator, a flat nozzle type hot melt applicator, a roll type coater, an extrusion type coater, a printing machine, and a sprayer.

(3-3) Formation of supply-side flow path When the supply-side flow path material is a discontinuous member formed of a material different from that of the separation membrane main body, the formation of the supply-side flow path material includes a permeation-side flow path. The same methods and timings as the material formation can be applied.

  Further, a difference in height can be imparted to the supply side of the separation membrane by a method such as embossing, hydraulic forming, or calendering.

  Examples of the embossing method include roll embossing, and the pressure and processing temperature for carrying out this can be appropriately determined according to the melting point of the separation membrane. For example, when the separation membrane has a porous support layer containing an epoxy resin, the linear pressure is preferably 10 kg / cm or more and 60 kg / cm or less, and the heating temperature is preferably 40 ° C. or more and 150 ° C. or less. Moreover, when it has a porous support layer containing heat resistant resins, such as polysulfone, it is preferable that it is 10 to 70 kg / cm of linear pressure, and roll heating temperature 70 to 160 degreeC is preferable. In any case of roll embossing, a winding speed of 1 m / min to 20 m / min is preferable.

  When embossing is performed, the shape of the roll handle is not particularly limited, but it is important to reduce the pressure loss of the flow path and stabilize the flow path when supplying and permeating fluid to the separation membrane element. is there. In these respects, an ellipse, a circle, an ellipse, a trapezoid, a triangle, a rectangle, a square, a parallelogram, a rhombus, an indefinite shape, and the like are adopted as the shape observed from the upper surface. In addition, three-dimensionally, it may be formed so that the width becomes smaller as the height is higher, or conversely, it may be formed so that the width becomes wider as the height is higher, regardless of the height. They may be formed with the same width.

  The difference in height on the supply-side surface of the separation membrane that can be imparted by embossing can be freely adjusted by changing the pressure heat treatment conditions so as to satisfy the conditions that require separation characteristics and water permeation performance.

  As described above, when the supply-side flow path is formed by fixing the supply-side flow path material to the separation membrane main body, or when the supply-side flow path material is formed by roughening the membrane, these supplies are supplied. The step of forming the side channel may be regarded as one step in the separation membrane manufacturing method.

  When the supply-side flow path is a continuously formed member such as a net, after the separation membrane is manufactured by arranging the permeation-side flow path material in the separation membrane body, the separation membrane and the supply-side flow are What is necessary is just to overlap with a road material.

(3-4) Formation of separation membrane leaf As described above, the separation membrane leaf may be formed by folding the separation membrane so that the surface on the supply side faces inward, or two separate sheets The separation membrane may be formed by bonding so that the surfaces on the supply side face each other.

  The manufacturing method of the separation membrane element preferably includes a step of sealing the inner end portion in the winding direction of the separation membrane on the surface on the supply side. In the sealing step, the two separation membranes are overlapped so that the surfaces on the supply side face each other. Furthermore, the inner end in the winding direction of the stacked separation membranes, that is, the left end in FIG. 6A is sealed.

  Examples of the method of “sealing” include adhesion by an adhesive or hot melt, fusion by heating or laser, and a method of sandwiching a rubber sheet. Sealing by adhesion is particularly preferable because it is the simplest and most effective.

  At this time, a supply-side channel material formed separately from the separation membrane may be disposed inside the overlapped separation membrane. As described above, the arrangement of the supply-side flow path material can be omitted by providing a height difference in advance on the supply-side surface of the separation membrane by embossing or resin coating.

  Either the supply-side sealing or the permeation-side sealing (envelope-like membrane formation) may be performed first, or the supply-side sealing is performed while stacking separation membranes. And the sealing of the surface on the transmission side may be performed in parallel. However, in order to suppress the generation of wrinkles in the separation membrane during winding, the adhesive or hot melt at the end in the width direction is allowed to allow the adjacent separation membranes to shift in the length direction due to winding. It is preferable to complete the solidification or the like, that is, the solidification for forming an envelope-like film, after the winding is completed.

(3-5) Formation of Envelope-shaped Membrane Folding and attaching one separation membrane so that the surface on the permeate side faces inward, or so that the surface on the permeate side faces two inner surfaces An envelope film can be formed by overlapping and bonding. In the rectangular envelope film, the other three sides are sealed so that only one end in the length direction is opened. Sealing can be performed by bonding with an adhesive or hot melt, or by fusion with heat or laser. However, the “envelope membrane” is also included in the “separation membrane leaf” in that it includes the surface on the fluid permeation side and the flow path material.

  The adhesive used for forming the envelope film preferably has a viscosity in the range of 40P to 150P, and more preferably 50P to 120P. If the adhesive viscosity is too high, wrinkles are likely to occur when the laminated separation membrane leaf is wound around a water collection tube. Wrinkles may impair the performance of the separation membrane element. On the other hand, when the adhesive viscosity is too low, the adhesive may flow out from the end of the separation membrane leaf to contaminate the device. Moreover, when an adhesive adheres to a portion other than the portion to be bonded, the performance of the separation membrane element is impaired, and the work efficiency is significantly reduced due to the processing operation of the adhesive that has flowed out.

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

  As the adhesive, a urethane-based adhesive is preferable, and in order to make the viscosity in the range of 40 P or more and 150 P or less, the isocyanate of the main agent and the polyol of the curing agent have an isocyanate / polyol weight ratio of 1/5 or more and 1 or less. Such a mixture is preferred. The viscosity of the adhesive is obtained by measuring the viscosity of a mixture in which the main agent, the curing agent alone, and the mixture ratio are defined in advance with a B-type viscometer (JIS K 6833).

(3-6) Winding of separation membrane A conventional element manufacturing apparatus can be used for manufacturing a separation membrane element. In addition, as an element production method, a method described in a reference document (Japanese Patent Publication No. 44-14216, Japanese Patent Publication No. 4-11928, Japanese Unexamined Patent Publication No. 11-226366) is used. it can. Details are as follows.

  When the separation membrane is wound around the water collecting pipe, the separation membrane is disposed so that the closed end of the separation membrane leaf, that is, the closed portion of the envelope-shaped membrane faces the water collecting pipe. By winding the separation membrane around the water collecting pipe in such an arrangement, the separation membrane is wound in a spiral shape.

  If a spacer such as a tricot or base material is wound around the water collection pipe, the adhesive applied to the water collection pipe will not flow easily when the element is wound, leading to suppression of leakage, and the flow path around the water collection pipe is stable. Secured. The spacer may be wound longer than the circumference of the water collecting pipe.

(3-7) Other steps The method for producing a separation membrane element may include further winding a film, a filament, and the like around the outer periphery of the wound membrane 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 separation membrane element may be further used as a separation membrane module by being connected in series or in parallel and housed in a pressure vessel.

  In addition, the separation membrane element and the separation membrane module described above can be combined with a pump that supplies fluid to them, a device that pretreats the fluid, and the like to form 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 to obtain water that meets the purpose.

  The higher the operating pressure of the fluid separator, the higher the removal rate, but the energy required for operation also increases, and considering the retention of the separation membrane element supply channel and permeation channel, the membrane module The operating pressure when passing through the water to be treated is preferably 0.2 MPa or more and 5 MPa or less. As the raw water temperature increases, the salt removal rate decreases, but as the raw water temperature decreases, the membrane permeation flux also decreases. Moreover, when the pH of the raw water is in a neutral region, even if the raw water is a high salt concentration liquid such as seawater, the generation of scales such as magnesium is suppressed, and the deterioration of the membrane is also suppressed.

  The fluid to be treated by the separation membrane element is not particularly limited, but when used for water treatment, as raw water, TDS (Total Dissolved Solids: total dissolved solids) of 500 mg / L or more and 100 g / L or less such as seawater, brine, drainage, etc. For example). In general, TDS indicates the total dissolved solid content, and is expressed by “mass / volume”, but 1 L may be expressed as 1 kg and may be expressed by “weight ratio”. According to the definition, the solution filtered through a 0.45 μm filter can be calculated from the weight of the residue by evaporating at a temperature of 39.5 ° C. or higher and 40.5 ° C. or lower. Convert.

〔Example〕
The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples.

(Permeate side channel material height)
Using a scanning electron microscope (S-800) (manufactured by Hitachi, Ltd.), 30 cross sections of 30 arbitrary projections were photographed at 30 times, and the transmission side channel material height a was measured at 100 locations by the method described above. Then, the average value was calculated as the channel material height.

(Permeation-side channel material spacing and width)
Using a scanning electron microscope (S-800) (manufactured by Hitachi, Ltd.), a photograph of 30 sections of any protrusions was photographed at a magnification of 30 times, and the transmission-side channel material interval b and the transmission-side channel material width d were described above. 100 points were measured by the above-described method, and the average value was calculated as the channel material interval and width.

(Bottom position of permeate side channel material in the separation membrane leaf width direction)
The separation membrane element was cut into a plane perpendicular to the separation membrane leaf membrane surface and parallel to the width direction, and a cross-section was observed using a microscope (VHX-1000) manufactured by Keyence Corporation. Measured at 100 locations, and as shown in FIG. 5 (a), the bottom side positions of all the permeation-side channel materials existing in the vertical direction of the separation membrane leaf are not on the same straight line as the straight line perpendicular to the bottom side. When there are 10 or more parts including one or more, “the separation membrane leaf width of the permeation side channel material fixed to the surface on the permeation side of the separation membrane leaf and the permeation side channel material adjacent in the vertical direction of the separation membrane leaf The base position in the direction does not match. "

(Distance between the bottom side position in the width direction of the separation membrane leaf between the permeation side flow channel material fixed to the permeation side surface of the separation membrane leaf and the permeation side flow channel material fixed to the separation membrane leaf adjacent to the separation membrane leaf)
The separation membrane element was cut into a plane perpendicular to the separation membrane leaf membrane surface and parallel to the width direction, and a cross-section was observed using a microscope (VHX-1000) manufactured by Keyence Corporation. As shown in FIG. 5 (b), the permeate-side channel material closest in the width direction among the base-side position in the width direction of the separation membrane leaf and the permeate-side channel material fixed to the separation membrane leaf adjacent to the separation membrane leaf The distance i in the width direction of the separation membrane was measured. Measurement was performed at 100 locations, and the average value was calculated as the distance.

(An angle formed by the inner edge of the separation membrane leaf and the inner edge of the separation membrane leaf adjacent to the separation membrane leaf)
Disassemble the separation membrane element, and measure the angle j formed between the adjacent separation membrane leaves at the water collection tube side edge in the separation membrane leaf width direction of the disassembled separation membrane element as shown in FIG. 5 (c). did. The average value of all adjacent separation membrane leaves was calculated as an angle.

(Adhesive width uniformity)
As for the width of the adhesive at the width direction both ends on the separation membrane permeation side, the obtained separation membrane element was disassembled, and the width of the sealing portion at each end was measured at 100 locations. Then, the maximum value / minimum value was calculated and defined as the adhesive width uniformity.

(Performance change before and after separation membrane element winding)
The wound separation membrane element was stored at room temperature for 100 days. Thereafter, the separation membrane element was disassembled and the separation membrane performance was measured. The disassembled separation membrane was operated for 200 hours under the conditions of 2,000 ppm salt as raw water, operating pressure 1.5 MPa, operating temperature 25 ° C., pH 6.5. Thereafter, permeated water was obtained by operating for 10 minutes under the same conditions. About the permeated water obtained by this 10-minute driving | operation, TDS density | concentration was calculated | required by conductivity measurement. The disassembled separation membrane leaf was divided into 100 parts and measured at 100 locations, and the average value of all the separation membrane leaves was calculated. The separation membrane TDS concentration after element winding storage / separation membrane TDS concentration before element winding was defined as the performance change.

(Change in permeate-side channel material height before and after winding of separation membrane element)
The wound separation membrane element was stored at room temperature for 100 days. Thereafter, the separation membrane element was disassembled, and the change in the height of the permeation side channel material was measured. Permeation side channel material height after element winding storage / permeation side channel material height before element winding was calculated as a change in height.

Example 1
On a nonwoven fabric made of polyethylene terephthalate fiber (yarn diameter: 1 dtex, thickness: about 80 μm, air permeability: 1 cc / cm ² / sec, density: 0.76 g / cm ³ ), a DMF solution of 16.0% by weight of polysulfone is 165 μm. Cast at room temperature (25 ° C.), immediately immersed in pure water for 5 minutes, and immersed in warm water at 80 ° C. for 1 minute to form a porous support layer comprising a fiber-reinforced polysulfone support membrane ( A thickness of 135 μm) was produced.

  Thereafter, the surface of the polysulfone layer of the porous support membrane was immersed in a 2.0 wt% aqueous solution of m-PDA for 2 minutes, and then slowly pulled up in the vertical direction. Furthermore, the excess aqueous solution was removed from the surface of the support film by blowing nitrogen from the air nozzle.

  Thereafter, an n-decane solution containing 0.08% by weight of trimesic acid chloride was applied so that the surface of the film was completely wetted, and then allowed to stand for 1 minute. Thereafter, the excess solution was removed from the membrane by air blowing and washed with hot water at 85 ° C. for 1 minute.

  Next, polyethylene (trade name: 2208J) was applied to the permeation side surface of the separation membrane using a gravure roll while adjusting the temperature of the backup roll to 15 ° C. The resin temperature was 155 ° C., and the processing speed was 8 m / min. The pattern engraved on the surface of the gravure roll was a hemispherical dot with a diameter of 0.4 mm arranged in a staggered pattern. The obtained permeation-side channel material had a height of 290 μm and a width of 390 μm.

The separation membrane thus obtained was folded and cut so that the effective area at the separation membrane element was 37.0 m ^2, and the net (thickness: 0.75 mm, pitch: 5 mm × 5 mm, fiber diameter: 0) 26 leaves having a width of 900 mm and a leaf length of 800 mm were prepared using a supply side channel material of .39 mm and a projected area ratio of 0.12).

  The permeate-side channel material is laminated on the permeate-side surface of the obtained leaf, and is wound spirally around an ABS water collecting pipe (width: 1,020 mm, diameter: 30 mm, number of holes 40 × 1 linear row), A film was further wound around the outer periphery. After fixing with tape, edge cutting, end plate attachment, and filament winding were performed to produce an 8-inch element. Both end plates were perforated end plates. That is, in this example, the separation membrane element shown in FIG. The position of the bottom side of the separation membrane leaf width direction of the permeation side channel material, the permeation side flow channel material secured to the permeation side surface of the separation membrane leaf and the permeation side flow channel material secured to the separation membrane leaf adjacent to the separation membrane leaf The distance between the bottom positions in the width direction of the separation membrane leaf and the angle formed between the inner edge of the separation membrane leaf and the inner edge of the separation membrane leaf adjacent to the separation membrane leaf were the values shown in Table 1. The obtained separation membrane element was disassembled, and the adhesive width uniformity, the performance change before and after winding the separation membrane element, and the permeation-side channel material height change before and after winding the separation membrane element were evaluated. It was the value shown.

  Hereinafter, separation membranes were produced in the same manner as in Example 1 under conditions not specifically mentioned.

(Examples 2 to 8)
The position of the bottom side of the separation membrane leaf width direction of the permeation side channel material, the permeation side channel material adhered to the permeation side surface of the separation membrane leaf, and the permeation side channel material adhered to the separation membrane leaf adjacent to the separation membrane leaf The arrangement of the permeate-side channel material was changed so that the distance of the bottom side position in the separation membrane leaf width direction becomes the value shown in Table 1. Further, except that the separation membrane leaf is arranged so that the angle formed between the inner edge of the separation membrane leaf and the inner edge of the separation membrane leaf adjacent to the separation membrane leaf becomes the value shown in Table 1. 1 and was carried out in the same manner. The obtained separation membrane element was disassembled, and the adhesive width uniformity, the performance change before and after the separation membrane element winding, and the permeation side channel material height change before and after the separation membrane element winding were evaluated. Met.

(Examples 9 to 12)
The position of the bottom side of the separation membrane leaf width direction of the permeation side channel material, the permeation side channel material adhered to the permeation side surface of the separation membrane leaf, and the permeation side channel material adhered to the separation membrane leaf adjacent to the separation membrane leaf The arrangement of the permeate-side channel material was changed so that the distance of the bottom side position in the separation membrane leaf width direction becomes the value shown in Table 1. Further, the permeation side channel material was continuously arranged in the length direction of the separation membrane. Further, except that the separation membrane leaf is arranged so that the angle formed between the inner edge of the separation membrane leaf and the inner edge of the separation membrane leaf adjacent to the separation membrane leaf becomes the value shown in Table 1. 1 and was carried out in the same manner. The obtained separation membrane element was disassembled, and the adhesive width uniformity, the performance change before and after the separation membrane element winding, and the permeation side channel material height change before and after the separation membrane element winding were evaluated. Met.

(Comparative Examples 1 and 2)
The position of the bottom side of the separation membrane leaf width direction of the permeation side channel material, the permeation side channel material adhered to the permeation side surface of the separation membrane leaf, and the permeation side channel material adhered to the separation membrane leaf adjacent to the separation membrane leaf The arrangement of the permeate-side channel material was changed so that the distance of the bottom side position in the separation membrane leaf width direction becomes the value shown in Table 1. Further, except that the separation membrane leaf is arranged so that the angle formed between the inner edge of the separation membrane leaf and the inner edge of the separation membrane leaf adjacent to the separation membrane leaf becomes the value shown in Table 1. 1 and was carried out in the same manner. The obtained separation membrane element was disassembled, and the adhesive width uniformity, the performance change before and after the separation membrane element winding, and the permeation side channel material height change before and after the separation membrane element winding were evaluated. Met.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. In addition, the material, shape, dimension, numerical value, form, number, arrangement location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

  The membrane element of the present invention can be suitably used particularly for brine or seawater desalination.

DESCRIPTION OF SYMBOLS 1 Separation membrane 2 Separation membrane body 21 Supply side surface 22 Permeation side surface 201 Base material 202 Porous support layer 203 Separation functional layer 31 Permeation side flow path material 4 Separation membrane leaf 5 Permeation side flow path 6 Water collecting pipe 7 Separation membrane 71 Supply side surface 72 Permeation side surface 100 Separation membrane element a Separation membrane (leaf) length b Permeation side channel material width direction c Permeation side channel material height d Permeation side channel material width e Interval in length direction of permeation side flow path material f Length of permeation side flow path material R2 Region including from beginning to tail of permeation side flow path material arranged from inside to outside in winding direction in separation membrane R3 Separation membrane Region where the permeate-side flow path material is not provided at the outer end in the winding direction L1 Length of the entire separation membrane (the length a)
L2 Length of region R2 L3 Length of region R3

Claims (4)

Water collecting pipe,
A plurality of separation membrane leaves wound around each of the water collecting pipes in a stacked state,
Each of the separation membrane leaves is provided with a plurality of flow path members in the width direction of the separation membrane leaf on the surface on the fluid permeation side,
A separation membrane element in which a bottom position of a flow path material of one separation membrane leaf and a bottom position of a flow path material of at least one other separation membrane leaf are shifted in the width direction. The separation membrane element according to claim 1,
The distance between the bottom position of the flow path material of one separation membrane leaf and the bottom position of the flow path material of another separation membrane leaf adjacent to the one separation membrane leaf is 0.01 mm to Separation membrane element that is 2.5 mm. The separation membrane element according to claim 1 or 2,
A separation membrane element in which an angle formed by an inner edge of one separation membrane leaf and an inner edge of another separation membrane leaf adjacent to the one separation membrane leaf is 0 degree or more and 20 degrees or less. The separation membrane element according to any one of claims 1 to 3,
The flow path material is a separation membrane element that is continuous in a length direction orthogonal to the width direction.