JP2024149370A

JP2024149370A - Spiral separation membrane element, water treatment device using same, and water treatment method

Info

Publication number: JP2024149370A
Application number: JP2023218929A
Authority: JP
Inventors: 剛士誉田; 秀谷口; 健太朗高木
Original assignee: Toray Industries Inc
Current assignee: Toray Industries Inc
Priority date: 2023-04-05
Filing date: 2023-12-26
Publication date: 2024-10-18

Abstract

【課題】分離膜エレメントを運転したときの供給側流路のファウリングを抑制しながら、圧力損失を低減できる分離膜エレメントを提供することを課題とする。【解決手段】本発明の分離膜エレメントは、少なくとも集水管と、分離膜と、供給側流路材と、透過側流路材とを備えるスパイラル分離膜エレメントであって、前記分離膜エレメントの集水管の軸方向に対して垂直な断面において、集水管の中心と任意の外周を結ぶ直線上に位置する前記分離膜と前記供給側流路材によって形成される供給側流路Ｆについて、内周側の供給側流路の厚みが外周側の流路高さより小さく、前記供給側流路材の厚みＤが３５０μｍ以上６５０μｍ以下となることを特徴とする。【選択図】図５[Problem] The object of the present invention is to provide a separation membrane element capable of reducing pressure loss while suppressing fouling in the supply-side flow path during operation of the separation membrane element. [Solution] The separation membrane element of the present invention is a spiral separation membrane element comprising at least a water collection pipe, a separation membrane, a supply-side flow path material, and a permeate-side flow path material, characterized in that, in a cross section perpendicular to the axial direction of the water collection pipe of the separation membrane element, for a supply-side flow path F formed by the separation membrane and the supply-side flow path material located on a straight line connecting the center of the water collection pipe and an arbitrary outer periphery, the thickness of the supply-side flow path on the inner periphery side is smaller than the flow path height on the outer periphery side, and the thickness D of the supply-side flow path material is 350 μm or more and 650 μm or less. [Selected Figure] Figure 5

Description

本発明は、不純物を含む種々の液体から不純物を分離するため、特に海水の淡水化、かん水の脱塩、超純水の製造または排水処理などに用いるための分離膜エレメント、それを用いた水処理装置、水処理方法に関するものである。 The present invention relates to a separation membrane element for separating impurities from various liquids containing impurities, particularly for use in desalinating seawater, desalinating brackish water, producing ultrapure water, or treating wastewater, and to a water treatment device and method using the same.

海水およびかん水などに含まれるイオン性物質を除くための技術においては、近年、省エネルギーおよび省資源のためのプロセスとして、分離膜エレメントによる分離法の利用が拡大している。分離膜エレメントによる分離法に使用される分離膜は、その孔径や分離機能の点から、精密ろ過膜、限外ろ過膜、ナノろ過膜、逆浸透膜および正浸透膜に分類される。これらの膜は、例えば海水、かん水および有害物を含んだ水などからの飲料水の製造、工業用超純水の製造、並びに排水処理および有価物の回収などに用いられており、目的とする分離成分及び分離性能によって使い分けられている。 In recent years, the use of separation membrane elements as a technology for removing ionic substances contained in seawater and brine has been expanding as a process for saving energy and resources. The separation membranes used in separation membrane element separation methods are classified into microfiltration membranes, ultrafiltration membranes, nanofiltration membranes, reverse osmosis membranes, and forward osmosis membranes based on their pore size and separation function. These membranes are used, for example, to produce drinking water from seawater, brine, and water containing harmful substances, to produce ultrapure water for industrial use, as well as for wastewater treatment and recovery of valuable materials, and are used according to the target components to be separated and their separation performance.

分離膜エレメントとしては様々な形態があるが、分離膜の一方の面に原水を供給し、他方の面から透過流体を得る点では共通している。分離膜エレメントは、束ねられた多数の分離膜を備えることで、１個の分離膜エレメントあたりの膜面積が大きくなるように、つまり１個の分離膜エレメントあたりに得られる透過流体の量が大きくなるように形成されている。分離膜エレメントとしては、用途や目的にあわせて、スパイラル型、中空糸型、プレート・アンド・フレーム型、回転平膜型、平膜集積型などの各種の形状が提案されている。 Separation membrane elements come in a variety of shapes, but they all have in common that raw water is supplied to one side of the separation membrane and permeated fluid is obtained from the other side. Separation membrane elements are formed with many bundled separation membranes to increase the membrane area per separation membrane element, i.e., to increase the amount of permeated fluid obtained per separation membrane element. Various shapes of separation membrane elements have been proposed depending on the application and purpose, including spiral type, hollow fiber type, plate and frame type, rotating flat membrane type, and flat membrane integrated type.

例えば、逆浸透ろ過には、スパイラル分離膜エレメントが広く用いられる。スパイラル分離膜エレメントは、集水管と、集水管の周囲に巻き付けられた分離膜ユニットとを備える。分離膜ユニットは、供給水としての原水（つまり被処理水）を分離膜表面へ供給する供給側流路材、原水に含まれる成分を分離する分離膜、及び分離膜を透過し供給側流体から分離された透過流体を集水管へと導くための透過側流路材が積層されることで形成される。スパイラル分離膜エレメントは、原水に圧力を付与することができるので、透過流体を多く取り出すことができる点で好ましく用いられている。 For example, spiral separation membrane elements are widely used for reverse osmosis filtration. A spiral separation membrane element includes a water collection pipe and a separation membrane unit wrapped around the water collection pipe. The separation membrane unit is formed by stacking a feed-side flow passage material that supplies raw water (i.e., water to be treated) as feed water to the separation membrane surface, a separation membrane that separates components contained in the raw water, and a permeation-side flow passage material that guides the permeated fluid that has permeated the separation membrane and been separated from the feed-side fluid to the water collection pipe. Spiral separation membrane elements are preferably used because they can apply pressure to the raw water, allowing a large amount of permeated fluid to be extracted.

分離膜エレメントを用いて供給水を処理する際に、長期間分離膜エレメントを運転していると、供給水中の有機物やゴミなどの汚れ物質（ファウラント）が分離膜や供給側流路材に詰まっていくことがある（ファウリング）。ファウリングが生じると、圧力損失の増大やそれに伴う造水量の低下が引き起こされる。 When using a separation membrane element to treat feed water, if the separation membrane element is operated for a long period of time, organic matter, debris, and other contaminants in the feed water (foulants) can clog the separation membrane and the feed-side flow path material (fouling). When fouling occurs, it causes an increase in pressure loss and an associated decrease in the amount of water produced.

このようなファウリングによるエレメント性能低下を抑制するためには、例えば供給側流路材の厚さを厚くし、供給水が通過する供給側流路を広くすることでファウラントが詰まる箇所を少なくすることが挙げられる。しかし、供給側流路材の厚さを厚くすると分離膜エレメントに充填可能な分離膜の面積が減ってしまい、分離膜エレメントの透水性が低下する。 To prevent deterioration of element performance due to such fouling, for example, the thickness of the feed-side passage material can be increased and the feed-side passage through which the feed water passes can be widened to reduce the number of places where foulants can become clogged. However, increasing the thickness of the feed-side passage material reduces the area of separation membrane that can be packed into the separation membrane element, reducing the water permeability of the separation membrane element.

そこで、供給側流路材の形状を工夫した分離膜エレメントの性能向上が提案されている。具体的には、特許文献１では、供給側流路材中の繊維状物の交点と交点の間の繊維を細くすることで、圧力損失やファウリング性を低減させたネットが提案されている。 Therefore, it has been proposed to improve the performance of separation membrane elements by devising the shape of the feed-side flow path material. Specifically, Patent Document 1 proposes a net that reduces pressure loss and fouling by thinning the fibers between the intersections of the fibrous materials in the feed-side flow path material.

日本国特許第４１１９４２５号公報Japanese Patent No. 4119425

しかし、上記した分離膜エレメントは、分離膜エレメント全体の供給側流路高さが最適化されておらず、分離膜エレメントの性能を十分に発揮できていない場合があった。そこで、本発明は、分離膜エレメントの構造を制御することで、ファウリングを抑制しながら、圧力損失を低減できる分離膜エレメントを提供することを課題とする。 However, in the above-mentioned separation membrane element, the height of the supply side flow passage of the entire separation membrane element is not optimized, and there are cases where the performance of the separation membrane element is not fully demonstrated. Therefore, the objective of the present invention is to provide a separation membrane element that can reduce pressure loss while suppressing fouling by controlling the structure of the separation membrane element.

本発明およびその好ましい態様は、下記［１］～［９］の構成を有する。
［１］少なくとも集水管と、分離膜と、供給側流路材と、透過側流路材とを備えるスパイラル分離膜エレメントであって、前記分離膜エレメントの集水管の軸方向に対して垂直な断面において、集水管の中心と任意の外周を結ぶ直線上に位置する前記分離膜と前記供給側流路材によって形成される供給側流路Ｆについて、内周側の供給側流路の厚みが外周側の流路高さより小さく、前記供給側流路材の厚みＤが３５０μｍ以上６５０μｍ以下であることを特徴とする分離膜エレメント。
［２］前記供給側流路Ｆについて、外周側の供給側流路高さＤ_Ｏに対する内周側の供給側流路高さＤ_Ｉの比が０．９５０以下であることを特徴とする［１］に記載の分離膜エレメント。
［３］前記供給側流路材は一方向に並んだ複数の繊維状物Ａから構成される繊維状列Ｘおよび前記繊維状列Ｘとは異なる方向に並んだ複数の繊維状物Ｂから構成される繊維状列Ｙとが互いに立体交差して交点を形成したネット形状であり、前記繊維状物Ａおよび前記繊維状物Ｂの少なくとも一方は、太径部と細径部を有することを特徴とする、［１］または［２］に記載の分離膜エレメント。
［４］前記細径部の糸径に対する前記太径部の糸径の割合が１．５以上２以下であることを特徴する、［３］に記載の分離膜エレメント。
［５］前記繊維状物Ａおよび前記繊維状物Ｂの少なくとも一方の長手方向に垂直方向の断面の真円度が０ｍｍ以上０．２５ｍｍ以下であることを特徴とする、［３］に記載の分離膜エレメント。
［６］前記供給側流路材の平面から厚み方向に観察したとき、任意の交点と隣り合う交点間の繊維が一方から他方に向かってテーパー状繊維であることを特徴とする、［３］に記載の分離膜エレメント。
［７］前記分離膜エレメントの集水管長手方向の長さが５００ｍｍ以上であることを特徴とする、［１］または［２］に記載の分離膜エレメント。
［８］［１］または［２］に記載の分離膜エレメントを用いて被処理水を処理する水処理装置であって、［１］～［５］のいずれか一項に記載の分離膜エレメントを少なくとも２本以上直列に配置する水処理装置。
［９］［１］または［２］に記載の分離膜エレメントを用いて被処理水を処理する水処理方法であって、［１］または［２］に記載の分離膜エレメントを少なくとも２本以上直列に配置して使用する水処理方法。 The present invention and its preferred embodiments have the following configurations [1] to [9].
[1] A spiral separation membrane element comprising at least a water collection pipe, a separation membrane, a supply-side flow path material, and a permeate-side flow path material, wherein in a cross section perpendicular to the axial direction of the water collection pipe of the separation membrane element, for a supply-side flow path F formed by the separation membrane and the supply-side flow path material located on a straight line connecting the center of the water collection pipe and an arbitrary outer periphery, the thickness of the supply-side flow path on the inner periphery side is smaller than the flow path height on the outer periphery side, and the thickness D of the supply-side flow path material is 350 μm or more and 650 μm or less.
[2] The separation membrane element according to [1], wherein the ratio of the feed-side channel height D _I on the inner periphery side to the feed-side channel height D _O on the outer periphery side is 0.950 or less for the feed-side channel F.
[3] The separation membrane element according to [1] or [2], characterized in that the feed-side flow path material has a net shape in which a fibrous row X composed of a plurality of fibrous materials A aligned in one direction and a fibrous row Y composed of a plurality of fibrous materials B aligned in a direction different from the fibrous row X intersect with each other at three-dimensional intersections to form intersections, and at least one of the fibrous materials A and the fibrous materials B has a large diameter portion and a small diameter portion.
[4] The separation membrane element according to [3], wherein a ratio of a fiber diameter of the thick diameter portion to a fiber diameter of the thin diameter portion is 1.5 or more and 2 or less.
[5] The separation membrane element according to [3], wherein the circularity of a cross section perpendicular to the longitudinal direction of at least one of the fibrous material A and the fibrous material B is 0 mm or more and 0.25 mm or less.
[6] The separation membrane element according to [3], characterized in that, when observed in the thickness direction from a plane of the feed-side flow path material, the fibers between any intersection point and an adjacent intersection point are tapered fibers from one side to the other.
[7] The separation membrane element according to [1] or [2], wherein the length of the separation membrane element in the longitudinal direction of the water collection pipe is 500 mm or more.
[8] A water treatment device that treats water to be treated using the separation membrane element according to [1] or [2], in which at least two or more separation membrane elements according to any one of [1] to [5] are arranged in series.
[9] A water treatment method for treating water to be treated using the separation membrane element according to [1] or [2], in which at least two or more separation membrane elements according to [1] or [2] are arranged in series.

本発明によって、供給水がエレメントに流入するとき、流速が遅いところの流路を広くすることで、ファウリングを抑制し、薄い供給側流路材を搭載しても分離膜エレメント全体としての圧力損失を抑制できるため、透水性や脱塩率といった分離性能に優れた分離膜エレメントを得ることができる。 By widening the flow path where the flow rate is slow when the feed water flows into the element, the present invention can suppress fouling and suppress the pressure loss of the entire separation membrane element even when a thin feed-side flow path material is installed, resulting in a separation membrane element with excellent separation performance such as water permeability and salt rejection rate.

図１は、分離膜エレメントの一例を示す一部展開斜視図である。FIG. 1 is a partially developed perspective view showing an example of a separation membrane element. 図２は、供給側流路材の一例を示す平面図である。FIG. 2 is a plan view showing an example of the flow passage material on the supply side. 図３は、一般的な円管や平板間の流速分布を示す図である。FIG. 3 is a diagram showing the flow velocity distribution in a typical circular pipe or between flat plates. 図４は、分離膜エレメントに供給される流速分布の例を示す斜視図である。FIG. 4 is a perspective view showing an example of a flow rate distribution supplied to a separation membrane element. 図５は、本発明の分離膜エレメントの供給側流路高さパターンの例を示す図である。FIG. 5 is a diagram showing an example of a flow channel height pattern on the supply side of the separation membrane element of the present invention. 図６は、本発明以外の分離膜エレメントの供給側流路高さパターンの例を示す図である。FIG. 6 is a diagram showing an example of a feed-side flow channel height pattern of a separation membrane element other than that of the present invention. 図７は供給側流路高さのグラフを説明する図である。FIG. 7 is a diagram for explaining a graph of the supply side flow path height. 図８は、分離膜エレメントの流路高さを測定する方法を示した図である。FIG. 8 is a diagram showing a method for measuring the flow channel height of a separation membrane element. 図９（ａ）～図９（ｃ）は、本発明において、好ましい供給側流路材の態様を示す平面図である。9(a) to 9(c) are plan views showing preferred embodiments of the flow passage material on the feed side in the present invention. 図１０（ａ）および図１０（ｂ）は、供給側流路材の一例を示す平面図である。10(a) and 10(b) are plan views showing an example of a flow passage material on the supply side.

以下、本発明の実施の形態について、詳細に説明するが、本発明はこれらによって何ら限定して解釈されるものではない。 The following describes in detail the embodiments of the present invention, but the present invention should not be interpreted as being limited to these.

尚、本明細書において、「質量」は「重量」と同義である。また、本明細書において、「～」は、その前後に記載された数値を下限値および上限値として含むことを意味する。 In this specification, "mass" is synonymous with "weight." In addition, in this specification, "~" means that the numerical values before and after it are included as the lower and upper limits.

＜分離膜エレメント＞
本発明のスパイラル分離膜エレメントは、少なくとも集水管と、分離膜と、供給側流路材と、透過側流路材とを備える。 <Separation membrane element>
The spiral separation membrane element of the present invention comprises at least a water collection pipe, a separation membrane, a feed-side flow path material, and a permeate-side flow path material.

図１に示すスパイラル分離膜エレメント１では、供給側の流路を形成する供給側流路材２としては、高分子製のネットが使用されている。また、透過側流路材４としては、分離膜３の落ち込みを防ぎ、かつ透過側の流路を形成させる目的で、供給側流路材２よりも間隔が細かいトリコットが使用されている。透過側流路材４と該透過側流路材４の両面に重ね合わせて封筒状に接着された分離膜３とにより、封筒状膜５が形成される。封筒状膜５の内側が透過側流路を構成している。供給側流路材２と交互に積層された封筒状膜５は、開口部側の所定部分を集水管６の外周面に接着しスパイラル状に巻囲される。図１に示すｘ軸の方向が集水管６の長手方向である。またｙ軸、ｚ軸を含む平面方向が集水管６の長手方向と垂直な方向である。 In the spiral separation membrane element 1 shown in FIG. 1, a polymer net is used as the supply-side flow passage material 2 that forms the flow passage on the supply side. In addition, a tricot with finer spacing than the supply-side flow passage material 2 is used as the permeation-side flow passage material 4 in order to prevent the separation membrane 3 from falling and to form the flow passage on the permeation side. An envelope-shaped membrane 5 is formed by the permeation-side flow passage material 4 and the separation membrane 3 that is overlapped and adhered to both sides of the permeation-side flow passage material 4 in an envelope-like shape. The inside of the envelope-shaped membrane 5 constitutes the permeation-side flow passage. The envelope-shaped membrane 5, which is alternately laminated with the supply-side flow passage material 2, is spirally wound with a predetermined portion of the opening side adhered to the outer circumferential surface of the water collection tube 6. The direction of the x-axis shown in FIG. 1 is the longitudinal direction of the water collection tube 6. The planar direction including the y-axis and z-axis is perpendicular to the longitudinal direction of the water collection tube 6.

スパイラル分離膜エレメント１では、通常一方の側面から、供給水７が供給され、供給水７は、集水管６と平行に流れながら、透過水８と濃縮水９とに徐々に分離される。透過水８は、供給水７が供給される反対の側面からスパイラル分離膜エレメント１の外部へと出ていく。 In the spiral separation membrane element 1, the feed water 7 is usually supplied from one side, and as it flows parallel to the water collection pipe 6, it is gradually separated into permeate water 8 and concentrated water 9. The permeate water 8 exits the spiral separation membrane element 1 from the side opposite to the side to which the feed water 7 is supplied.

この方式においては、供給水７がスパイラル分離膜エレメント１の一方の側面から他方の側面へ流れるため必然的に膜に接している距離が十分にあり、それにより供給水７が、透過水８と濃縮水９とに十分に分離されるという特徴がある。 In this method, the feed water 7 flows from one side of the spiral separation membrane element 1 to the other side, so there is inevitably a sufficient distance where it is in contact with the membrane, which is a feature of the method, as it allows the feed water 7 to be sufficiently separated into permeate 8 and concentrate 9.

＜スパイラル分離膜エレメントの製造＞
（分離膜リーフの形成）
分離膜リーフは、分離膜の間に供給側流路材を挟みこみ、供給側の面が内側を向くように分離膜を折りたたむことで形成されてもよいし、別々の２枚の分離膜を、供給側の面が向かい合うようにして重ね合わせ、分離膜の周囲を封止することで形成されてもよい。 <Manufacturing of Spiral Separation Membrane Element>
(Formation of separation membrane leaf)
The separation membrane leaf may be formed by sandwiching a supply-side flow path material between separation membranes and folding the separation membranes so that the supply-side surface faces inward, or by overlapping two separate separation membranes with their supply-side surfaces facing each other and sealing the periphery of the separation membrane.

なお、「封止」する方法としては、接着剤またはホットメルトなどによる接着、加熱またはレーザなどによる融着、およびゴム製シートを挟みこむ方法が挙げられる。接着による封止は、最も簡便で効果が高いために特に好ましい。 Methods for "sealing" include adhesion using adhesives or hot melts, fusion using heat or lasers, and sandwiching a rubber sheet. Sealing using adhesives is particularly preferred as it is the simplest and most effective method.

（スパイラル分離膜エレメントの製造）
スパイラル分離膜エレメントは、中心パイプに取り付けられたベースとなる透過側流路材の上に、分離膜リーフと透過側流路材を、接着剤を塗布しながら交互に積層し、巻回することでスパイラル型とすることができる。この時、巻囲張力や部材の厚み、素材などをコントロールすることで、供給側流路の厚みを調整することができる。 (Manufacturing of spiral separation membrane elements)
A spiral separation membrane element can be made into a spiral type by alternately stacking separation membrane leaves and permeate side flow path materials while applying adhesive on a permeate side flow path material that serves as a base attached to a central pipe, and then winding it up. At this time, the thickness of the feed side flow path can be adjusted by controlling the winding tension, thickness of the members, material, etc.

＜スパイラル分離膜エレメントの構造＞
スパイラル分離膜エレメントは、均一な厚みの供給側流路材、均一な厚みの透過側流路材、均一な厚みの膜を用いて一定の張力で巻囲すると、基本的に均一な厚みの流路を形成することができる。しかしながら、円管や二平板間の流速分布は、乱流または層流によって形状は異なるが、図３に示すように壁面で最も遅く、円管の中心部で最も速いすり鉢状の速度分布となる。図１や図４に示すようにスパイラル分離膜エレメント１の端面からの集水管６の飛び出しが短く、スパイラル分離膜エレメント１の端面の上流側において供給水７が集水管６によって特に分断されていない場合、スパイラル分離膜エレメントの供給水が流入するとき、図４に示すように、外周側で流速が遅く、内周側で流速が速くなる。つまり、均一な流路よりも外周側の流路が広い流路分布を持ったエレメントの方が供給水が澱みやすい箇所の流路スペースを確保し、ファウリングを抑制することができる。更に、薄い供給側流路材を適用する際のエレメント全体の圧力損失を抑制することができる。本願では、特に分離膜エレメントの圧力損失が課題となる、分離膜エレメントの集水管長手方向の長さが５００ｍｍ以上の構成において特に有用である。同一直径を持つ分離膜エレメントにおいて、集水管長手方向の長さが長いほど、同一運転圧力で運転する際に分離膜エレメントの流量が多くなり、圧力損失が大きくなる。特に分離膜エレメントの集水管長手方向の長さが５００ｍｍ以上になると、分離膜エレメントの圧力損失低減が運転時の有効圧力確保に有効に働く。 <Structure of the spiral separation membrane element>
When a spiral separation membrane element is wound with a constant tension using a uniform thickness of a feed-side flow passage material, a uniform thickness of a permeation-side flow passage material, and a uniform thickness of a membrane, a flow passage of a basically uniform thickness can be formed. However, the flow velocity distribution between a circular pipe or two flat plates is a cone-shaped distribution in which the flow velocity is slowest at the wall and fastest at the center of the circular pipe, as shown in FIG. 3, although the shape differs depending on whether the flow passage material is turbulent or laminar. When the water collection pipe 6 protrudes short from the end face of the spiral separation membrane element 1 as shown in FIG. 1 or FIG. 4, and the feed water 7 is not particularly divided by the water collection pipe 6 upstream of the end face of the spiral separation membrane element 1, when the feed water flows into the spiral separation membrane element, the flow velocity is slow on the outer periphery side and fast on the inner periphery side, as shown in FIG. 4. In other words, an element with a flow passage distribution in which the flow passage on the outer periphery side is wider than that of a uniform flow passage can secure flow passage space at the places where the feed water is likely to stagnate, and can suppress fouling. Furthermore, the pressure loss of the entire element can be suppressed when a thin feed-side flow passage material is applied. In the present application, the present invention is particularly useful in a configuration in which the length of the separation membrane element in the longitudinal direction of the water collection pipe is 500 mm or more, in which pressure loss in the separation membrane element is an issue. For separation membrane elements having the same diameter, the longer the length in the longitudinal direction of the water collection pipe, the greater the flow rate of the separation membrane element when operated at the same operating pressure, and the greater the pressure loss. In particular, when the length of the separation membrane element in the longitudinal direction of the water collection pipe is 500 mm or more, the reduction in pressure loss of the separation membrane element is effective in ensuring effective pressure during operation.

そのため、本実施形態では分離膜エレメントの集水管に対して垂直な断面において、集水管の中心と任意の外周を結ぶ直線上に位置する分離膜と供給側流路材によって形成される供給側流路Ｆについて、外周側の供給側流路高さＤ_Ｏが内周側の供給側流路高さＤ_Ｉより大きい。このような流路高さ分布にする方法としては、最初に巻囲張力を強くし、その後巻囲張力を下げる方法や、一度、均一な厚みの流路を形成してから、外周側を少し巻き緩める方法、接着剤の塗布量を外周部で少なくすることで外周部の流路を広くする方法、スパイラル分離膜エレメントの外周側で、供給側流路材のピッチを狭くしたり、供給側流路材の素材を変えたり、外周部に当たる供給側流路材の一部に水に溶ける素材をコーティングして後から溶かすことで外周部を広くする方法や、透過側流路材の厚みをスパイラル分離膜エレメントの外周側で薄くなるように設計する方法などが可能である。 Therefore, in this embodiment, in a cross section perpendicular to the water collection pipe of the separation membrane element, for a feed-side flow passage F formed by a separation membrane and a feed-side flow passage material located on a straight line connecting the center of the water collection pipe and an arbitrary outer periphery, the feed-side flow passage height D _O on the outer periphery side is greater than the feed-side flow passage height D _I on the inner periphery side. Methods for achieving such a flow passage height distribution include a method of first increasing the winding tension and then decreasing the winding tension, a method of forming a flow passage of uniform thickness once and then loosening the winding on the outer periphery side a little, a method of widening the flow passage on the outer periphery by reducing the amount of adhesive applied on the outer periphery, a method of narrowing the pitch of the feed-side flow passage material on the outer periphery side of the spiral separation membrane element, a method of changing the material of the feed-side flow passage material, a method of coating a part of the feed-side flow passage material corresponding to the outer periphery with a water-soluble material and dissolving it later to widen the outer periphery, and a method of designing the thickness of the permeation-side flow passage material to be thinner on the outer periphery side of the spiral separation membrane element.

供給側流路Ｆにおける供給側流路高さＤ_ＦはＸ線ＣＴ装置を用いることで、非破壊で測定することができる。スパイラル分離膜エレメントの集水管の中心と任意の外周を結ぶ直線Ｌ上に位置する分離膜と供給側流路材によって形成される供給側流路Ｆについて、カット面からある程度離れた、カットの影響がない箇所を分析する必要があるため、カット面から集水管長手方向に平行な方向に２インチの位置から４インチの位置までの解析を行う。直線Ｌ上の平面で直線Ｌを中心とする縦３．５インチ×横１インチ×奥行き２インチの直方体を解析範囲とし、それぞれの流路の空間体積を測定する。
供給側流路高さＤ_Ｆを測定するとき、直方体によって切り取られる範囲において、流路の片端が中心パイプまたは外周のフィラメントワインディングに触れていると、流路体積が過小評価されてしまう。そのため、流路の両端が直方体の長辺によって切り取られている流路のみを有効とする。 The feed-side flow path height D F in the feed-side flow path _F can be measured non-destructively by using an X-ray CT device. For the feed-side flow path F formed by the separation membrane and the feed-side flow path material located on the line L connecting the center of the water collection pipe of the spiral separation membrane element to an arbitrary outer periphery, it is necessary to analyze a location that is some distance away from the cut surface and is not affected by the cut, so an analysis is performed from a position 2 inches to a position 4 inches from the cut surface in a direction parallel to the longitudinal direction of the water collection pipe. A rectangular parallelepiped with a length of 3.5 inches, a width of 1 inch, and a depth of 2 inches centered on the line L on a plane on the line L is set as the analysis range, and the spatial volume of each flow path is measured.
When measuring the supply side channel height D _F , if one end of the channel touches the central pipe or the outer filament winding in the area cut by the rectangular parallelepiped, the channel volume will be underestimated. Therefore, only the channels whose both ends are cut by the long sides of the rectangular parallelepiped are considered valid.

外周側の供給側流路高さＤ_Ｏは外周から２０％の流路の平均値を用いる。例えば、流路数が６０個存在する場合、外周から１２個の流路の平均値をＤ_Ｏとする。内周側の供給側流路高さＤ_Ｉは、集水管から２０％の流路の平均値を用いる。Ｄ_Ｏ及びＤ_Ｉを算出するとき、小数点が生じた場合は、四捨五入して整数値とする。本実施形態の好ましい範囲としては、Ｄ_Ｏ、外周から２０％～４０％の流路高さの平均値、４０％～６０％の流路高さの平均値、６０％～８０％の流路高さの平均値、Ｄ_Ｉの順に徐々に小さくなる（同値も含む）ことが好ましい。 The supply side flow path height D _O on the outer periphery side is the average value of the flow paths that are 20% from the outer periphery. For example, if there are 60 flow paths, the average value of the 12 flow paths from the outer periphery is D _O. The supply side flow path height D _I on the inner periphery side is the average value of the flow paths that are 20% from the water collection pipe. When calculating D _O and D _I , if a decimal point occurs, it is rounded off to an integer value. As a preferred range in this embodiment, it is preferable that the values gradually decrease in the order of D _O , the average value of the flow path height from 20% to 40% from the outer periphery, the average value of the flow path height from 40% to 60%, the average value of the flow path height from 60% to 80%, and D _I (including the same value).

（供給側流路高さパターン）
本実施形態の供給側流路高さのパターンとしては、図５（ａ）～（ｅ）に示すように、外周部の流路高さＤ_Ｏが大きく、内周側の供給側流路高さＤ_Ｉが小さい形状が例として挙げられる。図５のグラフの見方としては、図７に示すように、横軸が流路の位置、縦軸が流路高さであり、分離膜エレメントの外周側の流路高さがグラフの左側、内周側の流路高さがグラフの右側に位置するようにプロットしたときの分布を示している。 (Supply side flow path height pattern)
5(a) to 5(e), examples of the supply-side channel height pattern in this embodiment include a shape in which the channel height D _O on the outer periphery is large and the supply-side channel height D _I on the inner periphery is small. The graph in Fig. 5 can be read as shown in Fig. 7, where the horizontal axis represents the channel position and the vertical axis represents the channel height, and the distribution is shown when the channel height on the outer periphery side of the separation membrane element is plotted on the left side of the graph and the channel height on the inner periphery side is plotted on the right side of the graph.

本発明以外の従来の形態の供給側流路高さのパターンとして、図６のような均一な流路が例として挙げられる。 An example of a conventional supply side flow channel height pattern other than that of the present invention is a uniform flow channel as shown in Figure 6.

（Ｄ_Ｏに対するＤ_Ｉの比）
外周側の流路高さＤ_Ｏに対する内周側の供給側流路高さＤ_Ｉの比Ｄ_Ｉ／Ｄ_Ｏは、０．９５０以下が好ましい。Ｄ_Ｉ／Ｄ_Ｏがこの範囲であると、分離膜エレメントに流入する供給水のバランスが良く、ファウリング及び圧力損失を低減することができる。Ｄ_Ｉ／Ｄ_Ｏの下限値としては０．７５以上であることが好ましく、この範囲であると、分離膜エレメントに流入する供給水の流れが偏ることによる圧力損失を低減することができる。 (Ratio of _DI to _DO )
The ratio D _I /D _O of the inner circumferential side feed side channel height D _I to the outer circumferential side channel height D _O is preferably 0.950 or less. When D _I /D _O is in this range, the balance of the feed water flowing into the separation membrane element is good, and fouling and pressure loss can be reduced. The lower limit of D _I /D _O is preferably 0.75 or more, and when it is in this range, the pressure loss due to the bias of the flow of the feed water flowing into the separation membrane element can be reduced.

＜供給側流路＞
（供給側流路材）
スパイラル分離膜エレメントに用いられる供給側流路材は、一般に、図２に示すように、一方向に並んだ、繊維状物Ａ（２１）から構成される複数の繊維状列Ｘ、および繊維状列Ｘとは異なる方向に並んだ、繊維状物Ｂ（２２）から構成される複数の繊維状列Ｙから構成され、繊維状列Ｘと繊維状列Ｙとが互いに立体交差して複数の地点で交点を形成したネット形状をしている。 <Supply side flow path>
(Supply side flow path material)
As shown in FIG. 2 , the feed-side flow path material used in a spiral separation membrane element is generally composed of a plurality of fibrous rows X made of fibrous materials A (21) arranged in one direction, and a plurality of fibrous rows Y made of fibrous materials B (22) arranged in a direction different from that of the fibrous rows X, and the fibrous rows X and the fibrous rows Y intersect with each other at multiple points to form a net shape.

スパイラル分離膜エレメントにおいて、透過の駆動力は膜間差圧であるため、造水量を向上させるためには膜間差圧を増加させることが有効である。膜間差圧は、分離膜エレメントへの印加圧力から流動抵抗と浸透圧を差し引いたもので表される。よって、膜間差圧を増加させるには、印加圧力を大きくする、流動抵抗を下げる又は膜面浸透圧を下げることが必要である。膜面浸透圧は膜面濃度分極が生じることで増大する。供給側流路材の繊維状物は、供給水をかき乱す役割があり、膜面濃度分極を抑制するためには、繊維状物後方の膜面に供給水の渦（流れ）を生み出すことが重要である。 In spiral separation membrane elements, the driving force for permeation is the transmembrane pressure difference, so increasing the transmembrane pressure is effective in improving water production. The transmembrane pressure difference is expressed as the pressure applied to the separation membrane element minus the flow resistance and osmotic pressure. Therefore, to increase the transmembrane pressure difference, it is necessary to increase the applied pressure, reduce the flow resistance, or reduce the membrane surface osmotic pressure. The membrane surface osmotic pressure increases due to the occurrence of membrane surface concentration polarization. The fibrous material of the feed-side flow path material plays a role in disturbing the feed water, and in order to suppress membrane surface concentration polarization, it is important to create a vortex (flow) of the feed water on the membrane surface behind the fibrous material.

スパイラル分離膜エレメントに用いられる供給側流路材の形状は、膜と膜の間のスペースを確保できるものであれば、この形状に限らず、井桁状、波板状など様々なものを用いることができる。 The shape of the feed-side flow passage material used in the spiral separation membrane element is not limited to this shape, and various shapes such as a grid shape or a corrugated sheet can be used as long as it can secure space between the membranes.

（供給側流路材の厚み）
供給側流路材の平均厚さは、３５０μｍ以上６５０μｍ以下の範囲が好ましい。供給側流路材の平均厚さがこの範囲であれば、本実施形態において、分離膜エレメントへの膜面積を確保しつつ、圧力損失を低減し、膜面や供給側流路材に堆積し得るファウラントなどの物質が詰まりにくい十分な供給側流路を確保でき、ポンプの必要動力を大きくすることなく、長期にわたり安定的に分離膜エレメントの運転を行うことが可能となる。この範囲よりも供給側流路材が薄くなると、圧力損失が大きくなったり、ファウリングが進行しやすくなる原因になる。この範囲よりも供給側流路材が厚くなると、分離膜エレメントの分離膜面積を確保できなくなることと、ハンドリング性の観点で好ましくない。 (Thickness of the supply side channel material)
The average thickness of the feed-side channel material is preferably in the range of 350 μm to 650 μm. In this embodiment, if the average thickness of the feed-side channel material is in this range, the membrane area to the separation membrane element can be secured while reducing pressure loss, and a sufficient feed-side channel that is less likely to be clogged with substances such as foulants that may accumulate on the membrane surface or the feed-side channel material can be secured, and the separation membrane element can be stably operated for a long period of time without increasing the required power of the pump. If the feed-side channel material is thinner than this range, it may cause a large pressure loss or cause fouling to progress easily. If the feed-side channel material is thicker than this range, it may not be possible to secure the separation membrane area of the separation membrane element and it is not preferable from the viewpoint of handleability.

なお、交点部及び供給側流路材の厚みの測定には市販のマイクロスコープやＸ線ＣＴ測定装置を用いて、繊維状列に平行な縦断面を観察し、その距離を測定することで求めることができ、測定モードを用いて交点部または供給側流路材の厚みの任意の３０カ所の径を抽出して測定し、その平均値とすることができる。 The thickness of the intersections and the supply-side flow path material can be measured using a commercially available microscope or X-ray CT measuring device by observing a longitudinal section parallel to the fibrous rows and measuring the distance. Using the measurement mode, the diameters of any 30 points on the intersections or the thickness of the supply-side flow path material can be extracted and measured, and the average value can be calculated.

（供給側流路材の繊維形状）
本実施形態では、繊維状物Ａおよび繊維状物Ｂの少なくとも一方において、繊維状物の長手方向に沿って太径部と細径部を有すること、つまり繊維状物の長手方向に沿って糸径が変化していることが好ましい。繊維状物において、相対的に糸径が大きい部分を太径部、相対的に糸径が小さい部分を細径部と呼ぶ。 (Fiber shape of the feed side flow path material)
In this embodiment, it is preferable that at least one of the fibrous material A and the fibrous material B has a thick diameter portion and a thin diameter portion along the longitudinal direction of the fibrous material, that is, the thread diameter changes along the longitudinal direction of the fibrous material. In the fibrous material, the portion with a relatively large thread diameter is called the thick diameter portion, and the portion with a relatively small thread diameter is called the thin diameter portion.

浸透圧は、分離膜表面に生じる濃度分極が大きくなると上昇する。分離膜エレメントにおいて、供給水の流速が遅い場合であったり、膜面から流体が剥離したり、繊維の前後に流体が流れにくい状態であると、濃度分極の上昇に繋がる。すなわち、濃度分極を抑制するには、膜面流速を上げる、もしくは膜面に接する繊維を減らすことが効果的である。そこで、繊維状物Ａおよび繊維状物Ｂは、任意の繊維状列を含む縦断面において、繊維状列Ｘおよび繊維状列Ｙの細径部は分離膜の膜面と接触しないため、全体として分離膜の膜面に接する繊維が少なくなり、濃度分極の上昇を抑制できる。さらに、このような構成により、供給側流路材の空隙率が向上するため、排濁性を高め、流動抵抗の低減にも効果がある。 The osmotic pressure increases as the concentration polarization occurring on the separation membrane surface increases. In a separation membrane element, if the flow rate of the feed water is slow, if the fluid peels off from the membrane surface, or if the fluid is not easily able to flow in front of or behind the fibers, this leads to an increase in concentration polarization. In other words, to suppress concentration polarization, it is effective to increase the membrane surface flow rate or reduce the number of fibers in contact with the membrane surface. Therefore, in a longitudinal section including any fibrous row, the thin-diameter parts of fibrous row X and fibrous row Y of fibrous material A and fibrous material B do not contact the membrane surface of the separation membrane, so that the number of fibers in contact with the membrane surface as a whole is reduced, and the increase in concentration polarization can be suppressed. Furthermore, this configuration improves the porosity of the supply side flow path material, which is also effective in increasing turbidity removal and reducing flow resistance.

細径部の糸径に対する太径部の糸径の割合は１．５以上２以下の範囲が好ましい。細径部の糸径に対する太径部の糸径の割合がこの範囲であれば、より効果的に濃度分極の上昇を抑制し、排濁性を高め、流動抵抗を低減することが可能になる。供給側流路材の好ましい平均厚さの範囲及び細径部の糸径に対する太径部の糸径の好ましい割合の範囲を考慮すると、繊維状物の太径部は１７５μｍ以上３２５μｍ以下の範囲が好ましく、繊維状物の細径部は８７μｍ以上２１７μｍ以下の範囲が好ましい。 The ratio of the thread diameter of the thick diameter portion to the thread diameter of the thin diameter portion is preferably in the range of 1.5 to 2. If the ratio of the thread diameter of the thick diameter portion to the thread diameter of the thin diameter portion is in this range, it is possible to more effectively suppress an increase in concentration polarization, improve turbidity discharge, and reduce flow resistance. Considering the preferred range of the average thickness of the supply side flow path material and the preferred range of the ratio of the thread diameter of the thick diameter portion to the thread diameter of the thin diameter portion, the thick diameter portion of the fibrous material is preferably in the range of 175 μm to 325 μm, and the thin diameter portion of the fibrous material is preferably in the range of 87 μm to 217 μm.

また、繊維状物Ａおよび繊維状物Ｂの少なくとも一方において、繊維状物をその長手方向と垂直方向に切断したときの断面の真円度は、０ｍｍ以上０．２５ｍｍ以下の範囲であることが好ましい。真円度がこの範囲であれば、供給側流路材の流動抵抗を低減することが可能になる。真円度とは、「ＪＩＳＢ０６２１－１９８４幾何偏差の定義および表示」に記載の通り、円形形体を二つの同心の幾何学的円で挟んだとき、同心二円の間隔が最小となる場合の、二円の半径の差（ｍｍ）で表す。例えばキーエンス社製高精度形状測定システムＫＳ－１１００を用い、繊維状物の長手方向の糸径を測定し、その最大値を太径部の糸径、最小値を細径部の糸径として測定することができる。また、繊維状物の任意の部分を３０カ所抽出してその断面を観察し、それぞれの真円度の平均値を算出した。更に好ましい実施形態では、繊維状物Ａおよび繊維状物Ｂの少なくとも一方において、テーパー状をした部分を有する繊維で供給側流路材が構成されることである。繊維状物Ａおよび繊維状物Ｂの少なくとも一方がテーパー状の繊維で構成されることで、供給側流路材の剛性を保ちつつ、流動抵抗上昇の原因となる流体の急縮流・急拡流を抑制することができ、流動抵抗を低減できる。繊維状物Ａ、繊維状物Ｂは片方がテーパー状の繊維でもよいし、両方がテーパー状の繊維でもよい。 In addition, in at least one of the fibrous material A and the fibrous material B, the circularity of the cross section when the fibrous material is cut in the direction perpendicular to its longitudinal direction is preferably in the range of 0 mm to 0.25 mm. If the circularity is in this range, it is possible to reduce the flow resistance of the supply side flow path material. As described in "JIS B 0621-1984 Definition and Display of Geometric Deviation", the circularity is expressed as the difference (mm) between the radii of two concentric geometric circles when a circular shape is sandwiched between two concentric circles and the distance between the two circles is the smallest. For example, the KS-1100 high-precision shape measuring system manufactured by Keyence Corporation can be used to measure the thread diameter in the longitudinal direction of the fibrous material, and the maximum value is the thread diameter of the thick diameter part and the minimum value is the thread diameter of the thin diameter part. In addition, 30 arbitrary parts of the fibrous material were extracted, the cross sections were observed, and the average value of the circularity of each was calculated. In a further preferred embodiment, the supply-side flow passage material is made of fibers having a tapered portion in at least one of the fibrous material A and the fibrous material B. By making at least one of the fibrous material A and the fibrous material B a tapered fiber, it is possible to suppress the sudden contraction and expansion of the fluid, which causes an increase in flow resistance, while maintaining the rigidity of the supply-side flow passage material, thereby reducing the flow resistance. One of the fibrous material A and the fibrous material B may be a tapered fiber, or both may be tapered fibers.

本実施形態におけるテーパー状とは、繊維状物Ａと繊維状物Ｂが形成する交点と、隣り合う交点の間の繊維が一方から他方に向かって拡径している、具体的に、先細り形状または先太り形状になっていることを指す。ここでは、便宜上、テーパー状の繊維をテーパー、繊維が先細り形状になっておらず糸径が均一であるものを寸胴、交点間の繊維が細くなっており、ネッキングが存在する繊維をネッキングと呼称する。例えば、図９（ａ）～図９（ｃ）に示すような供給側流路材２ａ～２ｃにおける繊維状列の交点間の形状がテーパー、図１０（ａ）に示すような供給側流路材２ｄにおける繊維状列の交点間の形状が寸胴、図１０（ｂ）に示すような供給側流路材２ｅにおける繊維状列の交点間の形状がネッキングに当たる。 In this embodiment, the term "tapered" refers to an intersection formed by fibrous material A and fibrous material B, and the fibers between adjacent intersections expanding in diameter from one side to the other, specifically a tapered or thickened shape. For convenience, a tapered fiber is called a taper, a fiber with a uniform thread diameter that is not tapered is called a cylindrical fiber, and a fiber in which the fibers between the intersections become thinner and necking exists is called a necking fiber. For example, the shape between the intersections of the fibrous rows in the supply side flow channel material 2a to 2c shown in Figures 9(a) to 9(c) corresponds to a taper, the shape between the intersections of the fibrous rows in the supply side flow channel material 2d shown in Figure 10(a) corresponds to a cylindrical fiber, and the shape between the intersections of the fibrous rows in the supply side flow channel material 2e shown in Figure 10(b) corresponds to a necking.

図９（ａ）に示したように、供給側流路材２ａの平面に対して垂直な方向から観察したとき、繊維が一方から他方に先細り形状になっていればよい。先細り形状になっていることで、糸からの流体剥離を抑制し、流動抵抗を低くすることが出来る。好ましくは、図９（ｂ）及び図９（ｃ）に示したように、テーパー状の繊維が、一定の方向、具体的に供給水（原水）側から濃縮水側に向かって先細りとなった形状である。このような形状であれば、糸からの流体の剥離を抑制し、流体の急拡流および急縮流を防ぎ、流動抵抗を低減することが出来る。 As shown in Figure 9(a), when observed from a direction perpendicular to the plane of the supply side flow path material 2a, the fibers need only be tapered from one side to the other. The tapered shape can suppress fluid separation from the yarn and reduce flow resistance. Preferably, as shown in Figures 9(b) and 9(c), the tapered fibers are tapered in a certain direction, specifically from the supply water (raw water) side to the concentrated water side. Such a shape can suppress fluid separation from the yarn, prevent sudden expansion and contraction of the fluid, and reduce flow resistance.

また、供給側流路材の平面を観察したとき、繊維が重なり合う部分には、図９（ｂ）及び図９（ｃ）に示したように水かき部ｗが形成されることが好ましい。なお、「水かき部」とは、テーパー状繊維の太径部が重なり合ったときに形成される、平面視で繊維の中央部よりも幅広の部分をいう。供給側流路材に水かき部ｗが形成されると、それぞれの交点の強度が向上し、ネット全体の剛性が上がるため、定長寸法カットや装置通過性といった巻囲時のハンドリング性が上がったり、長期運転時にネットがズレにくくなる。 When observing the plane of the supply-side flow passage material, it is preferable that a web portion w is formed in the area where the fibers overlap, as shown in Figures 9(b) and 9(c). Note that a "web portion" refers to a portion that is formed when the thick-diameter portions of tapered fibers overlap, and is wider than the center of the fiber in a plan view. When web portions w are formed in the supply-side flow passage material, the strength of each intersection is improved and the rigidity of the entire net is increased, improving handling during winding, such as cutting to a fixed length and passing through equipment, and making the net less likely to shift during long-term operation.

また、繊維が寸胴形状やネッキングである場合に比べ、テーパー状であると、交点部の樹脂量が増え、交点部の形状が中央部に比べて幅広になりなだらかになるため、膜が傷つきにくく、除去率が低下しにくい。 In addition, compared to when the fibers are cylindrical or necked, tapered fibers increase the amount of resin at the intersections and make the intersections wider and more gentle than the center, so the membrane is less likely to be damaged and the removal rate is less likely to decrease.

また、ネッキングであると、糸径が細い割合が多いため、供給側流路面積率を上げやすく、供給側流路材の空隙率が大きくなり、排濁性を高め、流動抵抗を低くすることが出来る。しかし、テーパー形状と同一流路面積率で比較した場合、ネッキング形状であるとネッキング箇所で流路が急激に拡大もしくは縮小するため、局所的なファウリングやエネルギー損失が起き、差圧が大きくなる傾向にある。さらに、ネッキング形状は糸径が細い割合が多いため、剛性が低くなりやすい傾向にある。 In addition, with necking, the proportion of thin fibers is high, making it easier to increase the flow passage area ratio on the supply side, and the void ratio of the flow passage material on the supply side increases, improving turbidity removal and lowering flow resistance. However, when compared to a tapered shape at the same flow passage area ratio, the necking shape causes the flow passage to suddenly expand or contract at the necking point, which can lead to localized fouling and energy loss, and can increase the pressure difference. Furthermore, the proportion of thin fibers is high in the necking shape, so rigidity tends to be low.

（素材）
供給側流路材の素材は特に限定されないが、成形性の観点から熱可塑性樹脂が好ましく、特にポリエチレンおよびポリプロピレンは分離膜の表面を傷つけにくく、また安価であるので好適である。また、供給側流路材は、繊維状物Ａと繊維状物Ｂが同じ素材で形成されても構わないし、異なる素材で形成されていても構わない。 (material)
The material of the feed-side channel material is not particularly limited, but from the viewpoint of moldability, a thermoplastic resin is preferable, and in particular, polyethylene and polypropylene are preferable because they are unlikely to damage the surface of the separation membrane and are inexpensive. In addition, the feed-side channel material may be formed of the same material for the fibrous material A and the fibrous material B, or may be formed of different materials.

（製造方法）
ネット状の供給側流路材の成形は、一般的に内側と外側の２つの円周上に多数の孔を配置した内側と外側の２つの口金を逆方向に回転させながら、押出機から溶融させた樹脂を供給して、樹脂が口金から出る時または出た直後に内側と外側の口金から出る糸を溶融状態で交差させて溶融し網状構造を形成する。この段階ではネットは筒状の形状を取る。その後筒状のネットは冷却固化により厚みや糸径、交点部間隔を決定後、切開されてシート状ネットとして引き取られる。 (Production method)
In general, the formation of a net-shaped feed-side flow channel material involves rotating two die sets, one inside and one outside, with numerous holes arranged on the two circumferences of the inside and outside in the opposite directions while supplying molten resin from an extruder, and when or immediately after the resin comes out of the die sets, the threads coming out of the inside and outside die sets cross each other in a molten state to form a network structure. At this stage, the net takes on a cylindrical shape. The cylindrical net is then cooled and solidified to determine the thickness, thread diameter, and intersection interval, and is then cut open and taken off as a sheet-shaped net.

本実施形態のように、交点厚みが保たれたまま、交点部間の繊維状物において糸径が異なる領域が存在し、平面から見たときに繊維形状がテーパーである供給側流路材を製造するには、小さい口金孔から高い樹脂吐出圧で樹脂を供給し、筒状のネットの樹脂が完全に冷却固化する前に筒状ネットの内側に、筒状ネットの内径より径の大きい治具を通過させて、幅方向および長手方向に同時に引っ張りを加えながら冷却固化させる方法を採用することができる。筒状のネットの樹脂が完全に冷却固化する前に筒状ネットの内側に、筒状ネットの内径より径の大きい治具を通過させて作製したネットは、交点部から中央部にかけてなだらかに繊維状物の糸径が細くなることが特徴である。交点部間の繊維状物において糸径が均一である寸胴形状の供給側流路材を製造するには、口金孔から低い樹脂吐出圧で樹脂を供給し、筒状のネットの樹脂が完全に冷却固化する前に筒状ネットの内側に、筒状ネットの内径より径の大きい治具を通過させて、テーパー形状の供給側流路材よりも低い比率で幅方向および長手方向に同時に引っ張りを加えながら冷却固化させる方法を採用することが出来る。 To manufacture a supply-side flow passage material in which there are regions of different thread diameters in the fibrous material between the intersections while maintaining the intersection thickness as in this embodiment, and in which the fiber shape is tapered when viewed from above, a method can be adopted in which resin is supplied from a small nozzle hole at a high resin discharge pressure, and a jig with a diameter larger than the inner diameter of the tubular net is passed inside the tubular net before the resin in the tubular net is completely cooled and solidified, and the resin is cooled and solidified while simultaneously applying tension in the width and length directions. A net manufactured by passing a jig with a diameter larger than the inner diameter of the tubular net inside the tubular net before the resin in the tubular net is completely cooled and solidified is characterized by a gradual narrowing of the thread diameter of the fibrous material from the intersections to the center. To manufacture cylindrical supply-side flow passage material in which the fiber diameter is uniform between the intersections, a method can be used in which resin is supplied from the nozzle hole at a low resin discharge pressure, and before the resin in the cylindrical net is completely cooled and solidified, a jig with a diameter larger than the inner diameter of the cylindrical net is passed inside the cylindrical net, and the resin is cooled and solidified while being pulled in the width and length directions simultaneously at a lower rate than tapered supply-side flow passage material.

一方、一旦筒状のネットの冷却固化を行った後に再度、加熱炉内で縦延伸および横延伸を行う方法により製造されたネットは、交点部に対し中央部の繊維状物の糸径がネッキングした形状のネットを製造することが可能であり、ネットの糸形状を観察することで、両者の製造方法の違いを判別することができる。 On the other hand, when a tubular net is first cooled and solidified, and then stretched vertically and horizontally again in a heating furnace, it is possible to produce a net in which the diameter of the fibrous material in the center is necked relative to the intersection, and the difference between the two manufacturing methods can be distinguished by observing the shape of the net's threads.

なお、繊維状列の交点部間における中央部が交点部に比べて細径の糸で構成されたネットを製造する方法はこれらに限定されず、エンボス加工やインプリント加工、プレス法などにより交点部間の繊維状物を圧縮変形させる方法、金型に溶融樹脂を流延し取り出す方法、３Ｄプリンターを用いて製造しても構わない。 The method of manufacturing a net in which the central portion between the intersections of the fibrous rows is made of threads with a smaller diameter than the intersections is not limited to these, and may be a method of compressing and deforming the fibrous material between the intersections by embossing, imprinting, pressing, etc., a method of casting molten resin into a mold and removing it, or a method of using a 3D printer.

＜透過側流路＞
（透過側流路材）
封筒状膜５において、分離膜３は透過側の面を対向させて重ね合わされており、分離膜３同士の間には透過側流路材４が配置され、透過側流路材４によって透過側流路が形成される。透過側流路材の材料としては限定されず、トリコットや不織布、突起物を固着させた多孔性シート、凹凸成形し、穿孔加工を施したフィルム、凹凸不織布を用いることができる。また、透過側流路材として機能する突起物を分離膜の透過側に固着させてもよい。 <Permeation side flow path>
(Permeation Side Flow Channel Material)
In the envelope-shaped membrane 5, the separation membranes 3 are stacked with their permeate side surfaces facing each other, and a permeate-side flow path material 4 is disposed between the separation membranes 3, forming a permeate-side flow path by the permeate-side flow path material 4. There are no particular limitations on the material of the permeate-side flow path material, and tricot, nonwoven fabric, a porous sheet with protrusions attached, a film with a concave-convex shape and perforations, and a concave-convex nonwoven fabric can be used. In addition, protrusions functioning as the permeate-side flow path material may be attached to the permeate side of the separation membrane.

＜分離膜エレメントの利用＞
分離膜エレメントは、直列または並列に接続して圧力容器に収納されることで、分離膜モジュールとして使用されてもよいが、少なくとも２本以上直列に配置して使用するのが好ましい。システム全体として圧力損失を抑制しつつ、得られる造水量を増やすことが可能となる。 <Use of separation membrane elements>
The separation membrane elements may be connected in series or in parallel and housed in a pressure vessel to be used as a separation membrane module, but it is preferable to use at least two of them arranged in series, which makes it possible to increase the amount of water produced while suppressing pressure loss in the entire system.

また、上記の分離膜エレメント、分離膜モジュールは、それらに流体を供給するポンプや、その流体を前処理する装置などと組み合わせて、水処理装置を構成することができる。この水処理装置を用いることにより、例えば供給水を飲料水などの透過水と膜を透過しなかった濃縮水とに分離して、目的にあった水を得ることができる。 The above separation membrane elements and separation membrane modules can be combined with pumps that supply fluids to them and devices that pretreat the fluids to form a water treatment device. By using this water treatment device, for example, it is possible to separate the supply water into permeated water, such as drinking water, and concentrated water that did not permeate the membrane, thereby obtaining water that meets the purpose.

水処理装置の操作圧力は高い方が除去率は向上するが、運転に必要なエネルギーも増加すること、また、分離膜エレメントの供給流路、透過流路の保持性を考慮すると、分離膜モジュールに供給水を透過する際の操作圧力は、０．２ＭＰａ以上６ＭＰａ以下が好ましい。 The higher the operating pressure of the water treatment device, the higher the removal rate, but the more energy required for operation will be. Also, taking into consideration the retention of the supply flow path and permeation flow path of the separation membrane element, the operating pressure when permeating the supply water to the separation membrane module is preferably 0.2 MPa or more and 6 MPa or less.

供給水温度は、高くなると塩除去率が低下するが、低くなるにしたがい膜透過流束も減少するので、５℃以上４５℃以下が好ましい。 As the supply water temperature increases, the salt rejection rate decreases, but as the temperature decreases, the membrane permeation flux also decreases, so a temperature between 5°C and 45°C is preferable.

また、原水のｐＨが中性領域にある場合、原水が海水などの高塩濃度の液体であっても、マグネシウムなどのスケールの発生が抑制され、また、膜の劣化も抑制される。 In addition, when the pH of the raw water is in the neutral range, even if the raw water is a liquid with a high salt concentration such as seawater, the formation of scale such as magnesium is suppressed, and deterioration of the membrane is also suppressed.

（供給水）
本実施形態の分離膜エレメントへの供給水は特に限定されず、予め処理された水道水でもよく、海水やかん水、下廃水のように溶液中の不純物が多いものでもよい。例えば、水処理に使用する場合、原水（供給水）としては、海水、かん水、排水等の５００ｍｇ／Ｌ以上１００ｇ／Ｌ以下のＴＤＳ（ＴｏｔａｌＤｉｓｓｏｌｖｅｄＳｏｌｉｄｓ：総溶解固形分）を含有する液状混合物が挙げられる。一般に、ＴＤＳは総溶解固形分量を指し、「質量÷体積」で表されるが、１Ｌを１ｋｇと見なして「重量比」で表されることもある。定義によれば、０．４５μｍのフィルターで濾過した溶液を３９．５～４０．５℃の温度で蒸発させ残留物の重さから算出できるが、より簡便には実用塩分（Ｓ）から換算する。 (Water supply)
The water supplied to the separation membrane element of this embodiment is not particularly limited, and may be tap water that has been pretreated, or may be water with a large amount of impurities in the solution, such as seawater, brine, or sewage. For example, when used for water treatment, the raw water (supply water) may be a liquid mixture containing 500 mg/L to 100 g/L of TDS (Total Dissolved Solids), such as seawater, brine, or wastewater. In general, TDS refers to the total dissolved solids content, and is expressed as "mass/volume", but it may also be expressed as "weight ratio" assuming that 1 L is 1 kg. According to the definition, it can be calculated from the weight of the residue after evaporating a solution filtered through a 0.45 μm filter at a temperature of 39.5 to 40.5° C., but it is more convenient to convert it from the practical salinity (S).

以下に実施例によって本発明をさらに詳細に説明するが、本発明はこれらの実施例によってなんら限定されるものではない。 The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

（供給側流路材Ｐの作製）
ポリプロピレンを材料として、多数の小さい孔を配置した内側と外側の２つの口金を逆方向に回転させながら、押出機から溶融させた樹脂を高い吐出圧で供給して、網状構造を有する筒状ネットを成形した。さらに筒状のネットの樹脂が完全に冷却固化する前に筒状ネットの内側に、筒状ネットの内径より径の大きい治具を通過させて、幅方向および長手方向に同時に引っ張りを加えながら冷却固化させる方法により、交点部から中央部にかけてなだらかに繊維状物の糸径が細くなるテーパー形状の、表１に示す供給側流路材を作製した。なお、押出機からの溶融樹脂吐出圧、筒状ネットを通過させる治具の寸法、引き取り速度を変更し、最終的に表１の供給側流路材形状となるよう構造制御を行った。 (Preparation of supply side flow path material P)
Using polypropylene as a material, two die sets, one inside and one outside, each having a large number of small holes, were rotated in the opposite directions while molten resin was supplied from an extruder at a high discharge pressure to form a tubular net having a network structure. Furthermore, before the resin of the tubular net was completely cooled and solidified, a jig having a diameter larger than the inner diameter of the tubular net was passed inside the tubular net, and the resin was cooled and solidified while simultaneously pulling in the width direction and the length direction to produce a feed-side channel material shown in Table 1, which has a tapered shape in which the diameter of the fibrous material gradually decreases from the intersection to the center. The molten resin discharge pressure from the extruder, the dimensions of the jig passing through the tubular net, and the take-up speed were changed to control the structure so that the shape of the feed-side channel material in Table 1 was finally obtained.

（供給側流路材Ｑの作製）
ポリプロピレンを材料として、多数の孔を配置した内側と外側の２つの口金を逆方向に回転させながら、押出機から溶融させた樹脂を供給して、網状構造を有する筒状ネットを成形し、繊維形状が寸胴であるネットを製造した。なお、押出機からの溶融樹脂吐出圧、引き取り速度を変更し、最終的に表１、２の供給側流路材形状となるよう構造制御を行った。 (Preparation of supply side passage material Q)
Using polypropylene as the material, two die sets, one inside and one outside, each with a large number of holes arranged therein, were rotated in opposite directions while molten resin was fed from an extruder to form a cylindrical net having a mesh structure, and a net having a cylindrical fiber shape was manufactured. The discharge pressure of the molten resin from the extruder and the take-up speed were changed to control the structure so that the final shape of the feed-side flow path material in Tables 1 and 2 was obtained.

（供給側流路材Ｒの作製）
ポリプロピレンを材料とし、供給側流路材Ｑと同様の手順で作製した筒状のネットを一旦冷却固化させ、その後、加熱炉内で縦延伸次いで横延伸を逐次で行い、交点部に対し中央部の繊維状物の糸径がネッキングした形状のネットを製造した。なお、押出機からの溶融樹脂吐出圧、縦および横の延伸倍率、引き取り速度を変更し、最終的に表１の供給側流路材形状となるよう構造制御を行った。 (Preparation of supply side passage material R)
A cylindrical net made of polypropylene in the same manner as in the feed-side flow path material Q was cooled and solidified, and then stretched longitudinally and then transversely in a heating furnace to produce a net in which the diameter of the fibrous material in the center was necked relative to the intersection. The molten resin discharge pressure from the extruder, the longitudinal and transverse stretch ratios, and the take-up speed were changed to control the structure so that the final feed-side flow path material shape in Table 1 was obtained.

（供給側流路材の厚み測定）
供給側流路材を１０×１０ｃｍに切り出し、キーエンス社製ワンショット３Ｄ形状測定機ＶＲ－３０００を用い、供給側流路材の繊維状列に平行な縦断面を倍率２０倍で観察し、任意の交点部分の厚みを３０カ所抽出して測定し、その平均値を算出した。 (Measurement of thickness of flow passage material on the supply side)
The feed-side flow path material was cut into a size of 10 x 10 cm, and a longitudinal section parallel to the fibrous rows of the feed-side flow path material was observed at a magnification of 20 times using a one-shot 3D shape measuring instrument VR-3000 manufactured by Keyence Corporation. The thicknesses of 30 arbitrary intersections were extracted and measured, and the average value was calculated.

（供給側流路高さ）
分離膜エレメントを集水管長手方向に垂直な方向に、端部から６インチの位置から１２インチの位置でカットし、６インチの長さの円筒状サンプルを切り出した。流路構造を崩さないために、エレメントのカット面の両側から接着剤を全面に塗布し、エレメントの端部から接着剤をわずかに含浸させた。円筒状サンプルを６０度の中心角を持つ扇形を底面に持つ柱体にカットし、観察サンプルを得た。その後、扇状サンプルの重量変化がなくなるまで、４０℃に設定した真空オーブンで乾燥させた。ＧＥ社製Ｘ線ＣＴ測定装置Ｐｈｏｅｎｉｘｖ｜ｔｏｍｅ｜ｘｍ３００を用い、管電流１００μＡ、管電圧１５０ｋＶ、解像度１９．８μｍの条件でスキャンし、３Ｄ像を得た。その後、ＶＯＬＵＭＥＧＲＡＰＨＩＣＳ社製ＶＧＳＴＵＤＩＯＭＡＸで解析を行い、供給側流路高さを測定した。 (Supply side flow passage height)
The separation membrane element was cut in a direction perpendicular to the longitudinal direction of the water collection pipe, from the position 6 inches to the position 12 inches from the end, and a cylindrical sample with a length of 6 inches was cut out. In order to prevent the flow path structure from collapsing, adhesive was applied to the entire surface from both sides of the cut surface of the element, and the adhesive was slightly impregnated from the end of the element. The cylindrical sample was cut into a column having a sector shape with a central angle of 60 degrees on the bottom to obtain an observation sample. Then, the sector sample was dried in a vacuum oven set at 40 ° C. until there was no change in weight. Using a GE X-ray CT measuring device Phoenix v | tome | x m300, scanning was performed under conditions of a tube current of 100 μA, a tube voltage of 150 kV, and a resolution of 19.8 μm to obtain a 3D image. Then, analysis was performed using VGSTUDIOMAX manufactured by VOLUMEGRAPHICS, and the supply side flow path height was measured.

供給側流路高さの測定方法は、供給側流路の体積から求めることができる。図８に示すように、分離膜エレメントの集水管の軸方向に対して垂直な断面において、集水管の中心と任意の外周を結ぶ直線Ｌ上に位置する分離膜と供給側流路材によって形成される供給側流路Ｆを縦３．５インチ×横１インチ×奥行２インチの直方体の領域で区切り、それぞれの流路の空間体積を測定し、それぞれの流路に対応した供給側流路の体積を取得した。集水管や外周のフィラメントワインディングに流路の片端が触れている場合、他の流路に比べて体積が小さくなるため、公平に流路高さを比較することができない。そのため、流路の両端が縦３．５インチ×横１インチの長方形の領域における、縦線に触れている流路のみを解析した。得られる流路体積は供給側流路材込みの値であるため、供給側流路材の空隙率で割ることで供給側流路材を無視した流路体積を得ることができる。円弧の長さはＩｍａｇｅＪを用いて測定した。画面上のスケールに合わせて直線選択ツールでなぞり、ＳｅｔＳｃａｌｅで実寸とピクセルの関係を設定した。円弧に沿って折れ線選択ツールでなぞり、Ｍｅａｓｕｒｅを選択して円弧の長さを得た。流路の上下に円弧が存在するため、上下の円弧を測定し、それらの平均値を円弧の長さとした。流路の奥行きは解析範囲で既知の値であり、円弧の長さ、供給側流路材の空隙率を用いて式（１）により供給側流路の厚みＤ_Ｆを得た。 The height of the supply side flow path can be measured from the volume of the supply side flow path. As shown in FIG. 8, in a cross section perpendicular to the axial direction of the water collection pipe of the separation membrane element, the supply side flow path F formed by the separation membrane located on the straight line L connecting the center of the water collection pipe and an arbitrary outer periphery and the supply side flow path material was divided into rectangular areas of 3.5 inches long x 1 inch wide x 2 inches deep, the spatial volume of each flow path was measured, and the volume of the supply side flow path corresponding to each flow path was obtained. If one end of the flow path is in contact with the water collection pipe or the filament winding on the outer periphery, the volume is smaller than that of the other flow paths, so that the flow path height cannot be compared fairly. Therefore, only the flow paths in which both ends of the flow path are in contact with the vertical line in a rectangular area of 3.5 inches long x 1 inch wide were analyzed. Since the obtained flow path volume is a value including the supply side flow path material, the flow path volume ignoring the supply side flow path material can be obtained by dividing it by the porosity of the supply side flow path material. The length of the arc was measured using ImageJ. The line selection tool was traced according to the scale on the screen, and the relationship between the actual size and pixels was set with Set Scale. The arc length was obtained by tracing along the arc with the broken line selection tool and selecting Measure. Since arcs exist above and below the flow path, the upper and lower arcs were measured and their average value was used as the arc length. The depth of the flow path was a known value within the analysis range, and the thickness D _F of the supply side flow path was obtained by formula (1) using the arc length and the porosity of the supply side flow path material.

（供給側流路材の空隙率測定）
供給側流路材を５０ｃｍ×５０ｃｍの大きさにカットし、重量を測定し、単位面積当たりの重量（ｋｇ／ｍ^２）を計算した。得られた値を供給側流路材の厚みで割り、単位体積当たりの重量（ｋｇ／ｍ^３）を計算した。式（２）より、素材密度（ｋｇ／ｍ^３）を用いて供給側流路材の空隙率を計算した。 (Measurement of porosity of feed side channel material)
The feed-side channel material was cut to a size of 50 cm x 50 cm, and the weight was measured to calculate the weight per unit area (kg/ ^m2 ). The obtained value was divided by the thickness of the feed-side channel material to calculate the weight per unit volume (kg/ ^m3 ). The porosity of the feed-side channel material was calculated using the material density (kg/ ^m3 ) according to formula (2).

（供給側流路材太径部の糸径Ｄ_Ａ及び細径部の糸径Ｄ_Ｂ測定）
キーエンス社製高精度形状測定システムＫＳ－１１００を用い、繊維状物の糸径を計測した。繊維状物において隣接する交点間の部分を３０個の区間に等分に分割し、各区間の中心箇所の糸径を測定した。測定された３０個の糸径のうち、最大値をＤ_Ａ、最小値をＤ_Ｂとして算出した。 (Measurement of yarn diameter D _A in the thick diameter portion of the flow passage material on the supply side and yarn diameter D _B in the thin diameter portion)
The diameter of the fibrous material was measured using a high-precision shape measuring system KS-1100 manufactured by Keyence Corporation. The portion between adjacent intersections in the fibrous material was divided into 30 equal sections, and the diameter of the center of each section was measured. Of the 30 measured diameters, the maximum value was calculated as D _A and the minimum value was calculated as D _B.

（供給側流路材繊維状物の真円度測定）
キーエンス社製高精度形状測定システムＫＳ－１１００を用い、繊維状物の任意の部分を３０カ所抽出してその断面を観察し、それぞれの真円度の平均値を算出した。 (Measurement of circularity of fibrous material on the supply side of the flow path)
Using a high-precision shape measuring system KS-1100 manufactured by Keyence Corporation, 30 arbitrary parts of the fibrous material were extracted, the cross sections were observed, and the average value of the circularity of each was calculated.

＜実施例＞
（スパイラル分離膜エレメントの作製）
ポリエチレンテレフタレート繊維からなる不織布（繊度：１デシテックス、厚み：約９０μｍ、通気度：１ｃｃ／ｃｍ^２／ｓｅｃ、密度０．８０ｇ／ｃｍ^３）上にポリスルホンの１６．０質量％のＤＭＦ溶液を１８０μｍの厚みで室温（２５℃）にてキャストし、ただちに純水中に浸漬して５分間放置し、８０℃の温水で１分間浸漬することによって繊維補強ポリスルホン支持膜からなる、多孔性支持層（厚さ１３０μｍ）ロールを作製した。 <Example>
(Preparation of spiral separation membrane element)
A 16.0 mass % DMF solution of polysulfone was cast to a thickness of 180 μm at room temperature (25° C.) onto a nonwoven fabric made of polyethylene terephthalate fibers (fineness: 1 dtex, thickness: approximately 90 μm, air permeability: 1 cc/cm ² /sec, density 0.80 g/cm ³ ), and the cast was immediately immersed in pure water and left for 5 minutes, and then immersed in warm water at 80° C. for 1 minute to produce a roll of a porous support layer (thickness 130 μm) made of a fiber-reinforced polysulfone support membrane.

その後、多孔性支持膜のポリスルホンからなる層の表面をｍ－ＰＤＡの１．４質量％およびε－カプロラクタム１．０重量％を含む水溶液中に２分間浸漬してから、垂直方向にゆっくりと引き上げた。さらに、エアーノズルから窒素を吹き付けることで、支持膜表面から余分な水溶液を取り除いた。 Then, the surface of the polysulfone layer of the porous support membrane was immersed in an aqueous solution containing 1.4 mass% of m-PDA and 1.0 weight% of ε-caprolactam for 2 minutes, and then slowly lifted vertically. In addition, excess aqueous solution was removed from the surface of the support membrane by blowing nitrogen from an air nozzle.

その後、トリメシン酸クロリド０．０７質量％を含むｎ－デカン溶液を、膜の表面が完全に濡れるように塗布してから、１分間静置した。その後、膜から余分な溶液をエアブローで除去し、８０℃の熱水で１分間洗浄して、複合分離膜ロールを得た。 Then, an n-decane solution containing 0.07% by mass of trimesoyl chloride was applied so that the surface of the membrane was completely wetted, and then the membrane was left to stand for 1 minute. After that, excess solution was removed from the membrane with an air blower, and the membrane was washed with hot water at 80°C for 1 minute to obtain a composite separation membrane roll.

このように得られた分離膜を、分離膜エレメントでの有効面積が４７．０ｍ^２となるように折り畳み断裁加工し、ポリプロピレン製ネット（厚み：０．６ｍｍ）を供給水側流路材として挟み込んで分離膜リーフを作製した。 The separation membrane thus obtained was folded and cut so that the effective area of the separation membrane element was 47.0 ^m2 , and a polypropylene net (thickness: 0.6 mm) was sandwiched therebetween as a feed water side flow path material to produce a separation membrane leaf.

得られた分離膜リーフの透過側面に透過側流路材としてトリコット（厚み：０．２６ｍｍ）を積層し、リーフ接着剤を塗布して、ＰＶＣ（ポリ塩化ビニル）製集水管（幅：１０１６ｍｍ、径：４７．６ｍｍ、孔数４０個×直線状１列）に積層体を２０％巻囲するごとに巻囲張力を段階的に下げてスパイラル状に巻き付け、巻囲体の外周面をテープで固定後、両端のエッジカットと端板取り付けを行い、一方の側面から供給水が供給され濃縮水が排出される、直径が８インチの分離膜エレメントを作製した。 Tricot (thickness: 0.26 mm) was laminated on the permeation side of the obtained separation membrane leaf as the permeation side flow path material, leaf adhesive was applied, and the laminate was spirally wound around a PVC (polyvinyl chloride) water collection pipe (width: 1016 mm, diameter: 47.6 mm, number of holes: 40 x one linear row) with the wrapping tension gradually reduced each time 20% of the laminate was wrapped around it. After fixing the outer periphery of the wrapped body with tape, the edges were cut on both ends and end plates were attached, and a separation membrane element with a diameter of 8 inches was produced, from which feed water was supplied from one side and concentrated water was discharged.

（造水量）
分離膜エレメントを圧力容器に入れて、供給水として、温度２５℃、濃度３２０００ｐｐｍ、ｐＨ７．０のＮａＣｌ水溶液を用い、運転圧力５．５２ＭＰａ、回収率８％とした。２４時間運転した後に１分間のサンプリングを行い、１日あたりの造水量（ｍ^３／日）として表した。 (Water production volume)
The separation membrane element was placed in a pressure vessel, and an aqueous NaCl solution with a temperature of 25° C., a concentration of 32,000 ppm, and a pH of 7.0 was used as the feed water, the operating pressure was 5.52 MPa, and the recovery rate was 8%. After 24 hours of operation, a one-minute sample was taken and the amount of water produced per day (m ³ /day) was expressed.

（除去率（ＴＤＳ除去率））
造水量の測定における１分間の運転で用いた供給水およびサンプリングした透過水について、ＴＤＳ濃度を伝導率測定により求め、下記式からＴＤＳ除去率を算出した。 (Removal rate (TDS removal rate))
The TDS concentrations of the feed water and the sampled permeate used during the 1-minute operation in measuring the amount of water produced were determined by conductivity measurement, and the TDS removal rate was calculated from the following formula.

ＴＤＳ除去率（％）＝１００×｛１－（透過水中のＴＤＳ濃度／供給水中のＴＤＳ濃度）｝
（エレメント圧力損失）
分離膜エレメントを装填する円筒状圧力容器の上流側（供給水側）と下流側（濃縮水側）を長野計器製差圧計（型式ＤＧ１６）を介して配管で接続し、運転中のエレメント圧力損失を計測した。運転条件は、供給水流量は１５０Ｌ／分、運転圧力は１．０ＭＰａとし、供給水には逆浸透膜処理水を用いた。また、エレメント内部の気泡が抜けた後は透過水配管のコックを閉じ、実質的に膜ろ過が行えない状態、つまり供給水が全量濃縮水として排出される状態で運転を行いエレメント差圧（ｋＰａ）の測定を行った。 TDS removal rate (%)=100×{1-(TDS concentration in permeate water/TDS concentration in feed water)}
(Element pressure loss)
The upstream side (feed water side) and downstream side (concentrate water side) of the cylindrical pressure vessel in which the separation membrane element was loaded were connected by piping via a Nagano Keiki differential pressure gauge (type DG16), and the element pressure loss during operation was measured. The operating conditions were a feed water flow rate of 150 L/min, an operating pressure of 1.0 MPa, and reverse osmosis membrane treated water was used as the feed water. After the air bubbles inside the element were removed, the cock of the permeate water piping was closed, and the operation was performed in a state in which membrane filtration was essentially not possible, that is, the entire amount of the feed water was discharged as concentrated water, and the element differential pressure (kPa) was measured.

（ファウリング試験）
分離膜エレメントを圧力容器に入れて、供給水として海水を用い、運転圧力５．５ＭＰａ、温度２５℃、回収率８％の条件下で２４時間運転した後に１分間のサンプリングを行い、その時の初期造水量（ｍ^３／日）を得た。その後、４週間連続運転を行い、通水後造水量（ｍ^３／日）を得た。初期造水量と通水後造水量から、下記式（３）に従い、造水量低下率（％）を求めた。また通水後圧力損失から初期圧力損失を引いた値を圧力損失上昇として算出した。 (Fouling test)
The separation membrane element was placed in a pressure vessel and operated for 24 hours under conditions of an operating pressure of 5.5 MPa, a temperature of 25°C, and a recovery rate of 8% using seawater as the feed water, and then a one-minute sample was taken to obtain the initial water production volume ( ^m3 /day). Continuous operation was then performed for four weeks to obtain the water production volume after water flow ( ^m3 /day). From the initial water production volume and the water production volume after water flow, the water production volume reduction rate (%) was calculated according to the following formula (3). The pressure loss increase was calculated by subtracting the initial pressure loss from the pressure loss after water flow.

（実施例１）
作製したエレメントを圧力容器に入れて、上述の条件で評価したところ、結果は表１の通りであった。 Example 1
The produced element was placed in a pressure vessel and evaluated under the above-mentioned conditions. The results are shown in Table 1.

（実施例２～１４）
供給側流路を表１の通りにした以外は全て実施例１と同様にして、分離膜エレメントを作製した。 (Examples 2 to 14)
A separation membrane element was produced in the same manner as in Example 1, except that the feed side flow path was as shown in Table 1.

分離膜エレメントを圧力容器に入れて、実施例１と同条件で各性能を評価したところ、結果は表１の通りであった。 The separation membrane element was placed in a pressure vessel and the performance was evaluated under the same conditions as in Example 1, with the results shown in Table 1.

＜比較例＞
（比較例１～４）
供給側流路を表２の通りにした以外は全て実施例１と同様にして、分離膜エレメントを作製した。 Comparative Example
(Comparative Examples 1 to 4)
A separation membrane element was produced in the same manner as in Example 1, except that the feed side flow path was as shown in Table 2.

分離膜エレメントを圧力容器に入れて、上述の条件で各性能を評価したところ、結果は表２の通りであった。 The separation membrane element was placed in a pressure vessel and its performance was evaluated under the conditions described above, with the results shown in Table 2.

表１、２に示す結果から明らかなように、実施例１～１４の分離膜エレメントは、ファウリングと圧力損失を抑えつつ、優れた分離性能を安定して備えていると言える。 As is clear from the results shown in Tables 1 and 2, the separation membrane elements of Examples 1 to 14 can be said to have excellent and stable separation performance while suppressing fouling and pressure loss.

本発明の膜エレメントは、特に、ＲＯ浄水器としての利用や、かん水や海水の脱塩に好適に用いることができる。 The membrane element of the present invention is particularly suitable for use as an RO water purifier and for desalinizing brackish water or seawater.

本発明を特定の態様を用いて詳細に説明したが、本発明の意図と範囲を離れることなく様々な変更および変形が可能であることは、当業者にとって明らかである。 Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the present invention.

１スパイラル分離膜エレメント
２供給側流路材
２ａ～２ｅ供給側流路材
２１繊維状物Ａ
２２繊維状物Ｂ
３分離膜
４透過側流路材
５封筒状膜
６集水管
７供給水
８透過水
９濃縮水
ｃ供給側流路材の供給水流れ方向に対して垂直方向の交点部間隔
ｄ供給側流路材の供給水流れ方向に対して平行方向の交点部間隔
ｗ水かき部
Ｌスパイラル分離膜エレメントの集水管の中心と任意の外周を結ぶ直線
Ｆ供給側流路
Ｄ_Ｆ供給側流路高さの平均値
Ｄ_Ｏ外周側から２０％の供給側流路高さの平均値
Ｄ_Ｉ内周側から２０％の供給側流路高さの平均値 1 Spiral separation membrane element 2 Supply side flow passage material 2a to 2e Supply side flow passage material 21 Fibrous material A
22 Fibrous material B
3 Separation membrane 4 Permeate side flow passage material 5 Envelope-shaped membrane 6 Water collection pipe 7 Supply water 8 Permeate water 9 Concentrated water c Intersection distance d of the supply side flow passage material in a direction perpendicular to the supply water flow direction Intersection distance w of the supply side flow passage material in a direction parallel to the supply water flow direction Wap portion L Straight line connecting the center of the water collection pipe of the spiral separation membrane element and an arbitrary outer periphery F Supply side flow passage D _F Average value of the supply side flow passage height D _O Average value of the supply side flow passage height of 20% from the outer periphery D _I Average value of the supply side flow passage height of 20% from the inner periphery

Claims

A spiral separation membrane element comprising at least a water collection pipe, a separation membrane, a supply side flow passage material, and a permeation side flow passage material, characterized in that in a cross section perpendicular to the axial direction of the water collection pipe of the separation membrane element, a supply side flow passage F formed by the separation membrane and the supply side flow passage material located on a straight line connecting the center of the water collection pipe and an arbitrary outer periphery is such that the thickness of the supply side flow passage on the inner circumference side is smaller than the flow passage height on the outer circumference side, and the thickness D of the supply side flow passage material is 350 μm or more and 650 μm or less.

2. The separation membrane element according to claim 1, wherein, for the supply side flow passage F, a ratio of a supply side flow passage height D _I on the inner periphery side to a supply side flow passage height D _O on the outer periphery side is 0.950 or less.

The separation membrane element according to claim 1 or 2, characterized in that the feed-side flow passage material has a net shape in which a fibrous row X consisting of a plurality of fibrous materials A arranged in one direction and a fibrous row Y consisting of a plurality of fibrous materials B arranged in a direction different from the fibrous row X cross each other three-dimensionally to form intersections, and at least one of the fibrous materials A and the fibrous materials B has a large diameter portion and a small diameter portion.

The separation membrane element according to claim 3, characterized in that the ratio of the thread diameter of the thick diameter portion to the thread diameter of the thin diameter portion is 1.5 or more and 2 or less.

The separation membrane element according to claim 3, characterized in that the circularity of the cross section perpendicular to the longitudinal direction of at least one of the fibrous material A and the fibrous material B is 0 mm or more and 0.25 mm or less.

The separation membrane element according to claim 3 , wherein when observed in a thickness direction from a plane of the feed-side flow path material, the fibers between any intersection point and an adjacent intersection point are tapered fibers from one side to the other.

The separation membrane element according to claim 1 or 2, characterized in that the length of the separation membrane element in the longitudinal direction of the water collection pipe is 500 mm or more.

A water treatment device that treats water to be treated using the separation membrane element according to claim 1 or 2, and that has at least two or more separation membrane elements according to claim 1 or 2 arranged in series.

A water treatment method for treating water to be treated using the separation membrane element according to claim 1 or 2, in which at least two or more separation membrane elements according to claim 1 or 2 are arranged in series.