JP3052958B1 - Spiral reverse osmosis membrane element and separation method - Google Patents

Abstract

An object of the present invention is to provide a liquid crystal display device in which, even under high-pressure and high-concentration operation conditions, deterioration due to deformation of a reverse osmosis membrane is small, pressure loss of the element is not so large, and performance degradation of the element due to concentration polarization is suppressed. Provided is a spiral reverse osmosis membrane element that can exhibit pressure resistance and separation performance. SOLUTION: A unit having a set of a supply liquid flow path material, two reverse osmosis membranes, and a permeate flow path material interposed between the reverse osmosis membranes is provided as a hollow water collecting pipe having a hole in the surface. Spiral type reverse osmosis membrane element wound around
A permeated liquid channel material, a woven or knitted fabric having an average thickness of at least 0.15 mm and not more than 0.4 mm having a plurality of grooves on at least one surface,
The average thickness of the woven or knitted fabric on the grooved surface is 0.05
mm and 0.2 mm or less, and the supply liquid flow path material has a distance X between diagonals perpendicular to the water collection pipe of 2 mm or more and 5 mm or less, and a distance Y between diagonals parallel to the direction. Is from 1.0 to 1.8 times X and has a mesh-like structure having an average thickness of from 0.5 mm to 1.0 mm. Membrane element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spiral reverse osmosis membrane, and more particularly to separating impurities from various liquids containing the impurities, and particularly to separating a highly concentrated solution such as desalination of seawater. The present invention relates to a novel spiral reverse osmosis membrane element for use in a device and a separation device using the same.

[0002]

2. Description of the Related Art In recent years, liquid separation using a reverse osmosis membrane has
It is attracting attention as an energy saving process and its use is increasing. In the reverse osmosis separation method, by passing a solution containing a solute such as a salt through a reverse osmosis membrane at a pressure higher than the osmotic pressure of the solution, it is possible to obtain a liquid in which the concentration of the solute such as a salt is reduced. For example, it is used for desalination of seawater, desalination of brackish water, production of ultrapure water, and wastewater treatment.

In a reverse osmosis membrane element, pressure is applied to a reverse osmosis membrane in order to efficiently separate and concentrate a liquid.
On the other hand, as shown in FIG. 1, the flow path on the permeated liquid side of the reverse osmosis membrane element secures a flow path for the permeated liquid and holds the reverse osmosis membrane without impairing the performance of the reverse osmosis membrane. ,
A permeate flow path material using a tricot having grooves parallel to one or both sides is incorporated.

As shown in FIG. 1, a flow path on the supply liquid side of the spiral reverse osmosis membrane element is secured on the supply liquid side to supply the supply liquid uniformly to the reverse osmosis membrane surface. At the same time, a supply liquid-side flow path member that has a role of disturbing the flow of the supply liquid and suppressing a decrease in element performance due to concentration polarization is incorporated. Concentration polarization means that impurities in the supply liquid are concentrated on the reverse osmosis membrane surface on the supply liquid side, and the impurity concentration on the membrane surface becomes higher than the impurity concentration on the supply liquid, increasing the osmotic pressure on the membrane surface and reducing the amount of fresh water Or the precipitation of insoluble substances such as gels and scales on the membrane surface, which lowers the element performance.
In the reverse osmosis method, it is a phenomenon that always occurs.

[0005]

Generally, when a high-concentration solution such as seawater desalination or fruit juice concentration is to be efficiently separated by a spiral reverse osmosis membrane element,
It is necessary to use a reverse osmosis membrane separation device in which a plurality of elements are incorporated in series, and to perform operation while applying a high pressure of 5.0 to 10.0 MPa to the elements. At this time, the reverse osmosis membrane element is required to have characteristics excellent in both pressure resistance and separation performance under high pressure and high concentration conditions.

With respect to pressure resistance, in a permeated liquid flow path material 2 using a tricot as shown in FIG. 2, which is employed in most of the conventional spiral type reverse osmosis membrane elements, the reverse osmosis membrane 1 has a tricot under high pressure. Of the permeated liquid flow path, and the performance is remarkably deteriorated. On the other hand, in order to improve the pressure resistance, for example, as shown in FIG. 3, small holes having a diameter of 0.05 mm to 0.1 mm are provided on the side of the tricot 7 having a groove at an interval of about 0.1 mm to 20 mm. By disposing a porous sheet 9 made of polyester having a thickness of 0.07 to 0.4 μm or the like, deformation of the reverse osmosis membrane under high pressure is prevented, and the membrane is damaged and the permeated liquid flow path is blocked. It is known to prevent. However, in this case, when the small hole diameter of the porous sheet is reduced and the interval between the small holes is increased, the small hole area of the entire sheet is small, so even if the sheet is thin, the rigidity of the sheet is sufficient. However, there is a case where the permeation resistance of the permeated liquid becomes extremely large and a sufficient performance cannot be obtained due to a pressure loss. Also, if the area of the small holes is increased to reduce the permeation resistance, the rigidity of the sheet decreases, so it is necessary to increase the thickness of the sheet, and a reverse osmosis membrane is loaded in a fixed volume like a spiral type element. When it is necessary to perform such a process, there is a problem that the membrane area of the reverse osmosis membrane that can be loaded in one element decreases, and a sufficient amount of permeate cannot be obtained.

In order to solve this problem, as a method of improving the membrane area per element, for example, the thickness of the supply liquid flow path material of the element is reduced, thereby increasing the membrane to be filled and permeating the membrane. It is conceivable to increase the area. Further, in this case, as an effect of reducing the thickness of the supply liquid flow path material, a decrease in element performance due to concentration polarization can be suppressed. This is because, by reducing the thickness of the supply liquid-side channel material, the linear velocity of the supply liquid on the film surface increases, the flow on the film surface becomes turbulent, and the concentration polarization layer becomes thin.

On the other hand, however, if the thickness of the supply liquid-side flow path material is reduced, impurities in the supply liquid or fouling substances due to microorganisms block the flow path on the supply liquid side, and the element performance deteriorates. The pressure loss increases, and the power required for the pump for supplying the supply liquid increases, resulting in a problem that the power cost increases. For this reason, in the conventional spiral reverse osmosis membrane element, the feed liquid side flow path material is of such a thickness that the pressure loss of the element is not so large, so that the permeation area of the membrane per element is small. Become smaller. In addition, as shown in FIG. 5, usually, the intervals X and Y between the intersections of the linear objects of the supply liquid side flow path material.
Are not equal to each other, it is not possible to sufficiently suppress the performance degradation of the element due to concentration polarization. Therefore, a reverse osmosis membrane element capable of exhibiting both excellent pressure resistance and separation performance under high pressure and high concentration conditions has not been obtained.

An object of the present invention is to provide a spiral reverse osmosis membrane element which can solve such problems and exhibit sufficient pressure resistance and separation performance under high pressure and high concentration conditions.

[0010]

Means for Solving the Problems The present invention relates to a method wherein "two reverse osmosis membranes are partially joined to each other, and the inside of the two reverse osmosis membranes is set to the permeate side". Spiral reverse osmosis membrane in which a unit consisting of a supply liquid side on the outside, a permeate flow path material on the permeate side, and a supply liquid flow path material on the supply liquid side is wound around the water collection pipe. In the element, the permeate flow path material has a plurality of grooves on at least one surface and has an average thickness of 0.15 mm or more and 0.4 mm or less, and is disposed on the surface of the woven or knitted material having the grooves. The average thickness was 0.1
A water-permeable cloth that is not less than 05 mm and not more than 0.2 mm, the supply liquid flow path material has a mesh structure composed of a plurality of linear objects, and the stitch is an intersection point in a direction perpendicular to the axis of the water collecting pipe. A spiral type reverse osmosis membrane element, wherein a distance X between the intersections is 2 mm or more and 5 mm or less, and a distance Y between the intersections in the axial direction is 1.0 times or more and 1.8 times or less of X. "A method for producing a liquid characterized by using the above spiral type reverse osmosis membrane element.", "A reverse method comprising connecting a pump and the above spiral type reverse osmosis membrane element in this order." Osmosis membrane separation apparatus "and" a first osmosis pump, a reverse osmosis membrane element, a second osmosis pump, and the above spiral type reverse osmosis membrane element are connected in this order. Device. "

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have conducted intensive studies on each of a permeate flow path material and a supply liquid flow path material by using many permeate flow path materials and supply liquid side flow path materials having different structures. Was done. As a result, an element with both excellent pressure resistance and high separation characteristics under high pressure and high concentration conditions such as seawater desalination can be obtained for a combination of a certain range of permeate flow path material and feed liquid flow path material. Was found. Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, as for the permeated liquid flow path material, the permeated liquid flow path material of the present invention is sandwiched between two reverse osmosis membrane elements 1 and has a groove having a groove on at least one surface as shown in FIG. Knitted fabric (in the present invention,
A woven or knitted fabric means a woven or knitted fabric. 10) and the water-permeable cloth 11 arranged on the surface having the grooves are the main constituent members.

In the present invention, the average thickness of the woven or knitted fabric constituting the permeate flow path material is 0.15 mm or more and 0.4 mm or less. If the thickness of the woven or knitted fabric constituting the permeated liquid flow path material is within the above range, a reverse osmosis membrane is formed when a water-permeable fabric described later is arranged on a surface of the woven or knitted fabric having a groove and incorporated into an element. A sufficient packed film area can be obtained by the combination of the liquid and the supply liquid channel material. The average thickness of the woven or knitted fabric is 0.15
mm or less, the packed membrane area can certainly be increased, but the flow resistance of the permeate increases because the size of the groove serving as the permeate flow channel described later cannot be sufficiently secured, and the separation performance decreases. This is not preferred. Also, 0.4
mm or more, the flow path of the permeated liquid can be sufficiently secured, but on the other hand, the area of the packed membrane when the element is formed becomes small,
There is a problem in that the amount of permeate per element is reduced, and when the woven or knitted material is thick, the rigidity is increased, and it is difficult to process into a spiral shape, which is not preferable.
A more preferable range of the average thickness of the woven or knitted fabric is 0.15 mm.
It is 0.3 mm or less.

The woven or knitted fabric has an average thickness of at least 10
It is preferable that the average value obtained by measuring the thickness of a point or more with a precision thickness gauge or the like be the average thickness of the present invention.

The woven or knitted fabric constituting the permeated liquid channel material has a structure having a groove on at least one surface. The size of the groove on the surface of the woven or knitted fabric is not particularly specified, but the groove width is 0.1 mm or more and 0.2 mm or less, the groove depth is 0.05 mm or more and 0.2 mm or less, and the pitch of the groove is 1
The range of 8 lines / cm or more and 25 lines / cm or less has a sufficiently low flow resistance with respect to the permeated liquid and a size sufficient to support the water-permeable cloth disposed on the surface under high pressure. Is preferred. More preferably, the groove width is 0.1
mm to 0.15 mm, the depth of the groove is 0.1 mm to 0.15 mm, and the pitch of the groove is 20 lines / cm to 23 lines / cm.

Here, regarding the groove width, groove depth and groove pitch, at least 10 points or more of groove width, groove depth, and groove pitch on a photograph magnified at a magnification of 10 to 50 times. It is preferable that the average value is obtained by measuring the pitch.

The type of the woven or knitted fabric of the permeate flow path material is not particularly limited as long as it has the above-mentioned structural characteristics, but it can be manufactured at high quality and at low cost. In view of this, it is preferable to use tricot as the woven or knitted fabric. Also, for tricots, for example, there are many types depending on the knitting organization, such as double denbi, Queen's code, three-piece mat,
Any material may be used as long as it secures a flow path for the permeated liquid and does not easily deform even under high pressure, and is not particularly limited.

The material of the woven or knitted fabric may be any material as long as it retains its shape as a channel material and has little elution of components into the permeate. For example, polyamide such as nylon, polyester, nylon, etc. Polyacrylonitrile,
Polyolefins such as polyethylene and polypropylene, polyvinyl chloride, polyvinylidene chloride, polyfluoroethylene, and carbon are listed.In particular, in consideration of the strength that can withstand high pressure and the ease of processing the woven or knitted fabric described later, polyester is used. It is preferable to use

In the present invention, in order to suppress deformation of the flow path material itself under high pressure, it is preferable to perform a hardening treatment for increasing the rigidity of the woven or knitted fabric. As a method of curing treatment,
For example, there is a method of impregnating a woven or knitted product with a resin such as melamine or epoxy, or a method of applying a heat fusion process of fusing and solidifying fibers by heating the woven or knitted material. In any of the above methods, any method can be used as long as it is a processing method capable of obtaining a hardness such that the channel material itself is not deformed.

Furthermore, in the present invention, in order to prevent local or non-uniform deformation of the water-permeable cloth or reverse osmosis membrane under high pressure, the woven or knitted material of the permeated liquid channel material may be subjected to calendering. good. By calendering, the woven or knitted fabric becomes very smooth and flat due to the undulations caused by the fiber shape. For this reason, the water-permeable nonwoven fabric and the reverse osmosis membrane do not undergo uneven deformation under high pressure, and the performance and durability can be further improved.

The present invention is characterized in that a cloth having water permeability is further disposed on the surface of the woven or knitted material having the grooves as described above.

With respect to the thickness of the water-permeable cloth, if it is too thin, the rigidity will be low and it will be deformed under high pressure. If it is too thick, the rigidity is good, but on the contrary, the flow path material itself will be too thick and the element will be too thick. Since there is a problem that the film area when incorporated into the element is reduced, and a problem that the permeation resistance is increased and the performance of the element is reduced, the average thickness is 0.05 mm or more.
The range is preferably 2 mm or less, more preferably 0.07 mm or more and 0.15 mm or less.

Here, the average thickness of the water-permeable fabric is preferably an average value obtained by measuring at least 10 points or more with a precision thickness gauge or the like as the average thickness of the present invention.

In the present invention, the type of the fabric is not particularly specified, but in terms of satisfying sufficient water permeability as a permeate flow path material and strength capable of withstanding deformation under high pressure.
It is preferable to use a nonwoven fabric.

The non-woven fabric is classified into two types: a non-woven fabric, which has no fiber orientation depending on the manufacturing method, a so-called non-oriented state, a fiber in which fibers are oriented in a certain direction, and a material intermediate between the two. Either of them may be used, but in order to provide the nonwoven fabric with sufficient rigidity in a certain thickness range, it is preferable to use one in which fibers are oriented in a certain direction.

Further, it is preferable that, when the nonwoven fabric in which the fibers are oriented in a certain direction is arranged on the surface of the woven or knitted fabric, the orientation direction of the fibers is orthogonal to the direction of the groove of the woven or knitted fabric.

This is because, when the fibers of the nonwoven fabric are oriented in a certain direction, the strength and rigidity of the nonwoven fabric become anisotropic, and deformations such as bending and bending are caused in a direction parallel to the orientation direction of the fibers. Because the vertical direction is stronger than the vertical direction, by making the groove direction of the woven or knitted fabric orthogonal to the orientation direction of the fibers of the nonwoven fabric,
This is because deformation of the nonwoven fabric under high pressure and falling into the groove of the woven or knitted fabric can be suppressed.

In the present invention, the degree of water permeability of the fabric,
That is, although the water permeability is not particularly specified, the permeability of pure water at 25 ° C. is 0.5 m ³ / (m ² · MPa · mi.
n) or more is preferable in order to reduce the permeation resistance of the nonwoven fabric. More preferably, 0.8 m ³ / (m ² · M
Pa · min) or more.

Further, the material of the water-permeable fabric of the present invention is not particularly specified, and any material may be used as long as it does not deform under pressure and the component is less eluted into the permeate. good. For example, polyamides such as nylon, polyester, polyacrylonitrile, polyolefins such as polyethylene and polypropylene, polyvinyl chloride, polyvinylidene chloride, and polyfluoroethylene can be used. It is preferable to use polyester as a material having good strength, high strength, and little elution of components into the permeate.

Next, the supply liquid flow path material, which is another important component in the spiral reverse osmosis membrane element of the present invention, will be described.

As for the supply liquid flow path material, the interval Y (12 in FIG. 5) of the linear structure and the direction perpendicular to the direction parallel to the axis of the water collection pipe of the supply liquid side flow path material shown in FIG. When the distance X (13 in FIG. 5) and the average thickness are selected, even if the performance of the reverse osmosis membrane itself is the same, the element performance, that is, the fresh water generation performance and the rejection performance are significantly increased without increasing the pressure loss of the element much. It can be improved.

If the distance between the linear objects constituting the supply liquid side flow path material is reduced, the chance of changing the flow direction of the supply liquid microscopically increases, so that the flow of the supply liquid is disturbed, and Since the concentration polarization layer is made thinner, the element performance is improved. However, if the pitch is too small, the flow resistance of the supply liquid increases, so that the pressure loss of the element increases.

As shown in FIG. 6 and FIG. 7, the supply liquid flows while spreading along the mesh line of the supply liquid side flow path material. If X is larger than Y with respect to the direction, the flow of the supply liquid tends to separate from the linear object, and the flow of the supply liquid is difficult to spread. On the other hand, when Y is large relative to X in the flow direction as shown in FIG. 7, the flow of the supply liquid is unlikely to be separated from the linear object, and flows along the linear object for a relatively long time. Because of the peeling, the flow of the supply liquid spreads. If the spread of the flow of the supply liquid is large, the supply liquid is uniformly supplied to the membrane surface, and there is also an effect of mixing the flow, so that the influence of concentration polarization can be reduced, and at the same time,
Since there is little flow separation, the flow resistance of the supply liquid is also small. Then, the angle of the mesh of the linear object (α (1 in FIG. 5)
4)) is 90 ° or less and 58 ° or more, preferably 85 ° or less and 61 ° or more, and more preferably 80 ° or less and 67 ° or more.

In summary, according to the present invention, X is 2 mm or more and 5 mm or less, preferably 2.5 mm or more and 4.5 mm or less, more preferably 3 mm or more and 4 mm or less, and Y is 1.0 times or more of X and 1.times. 8 times or less, preferably 1.1 times
This is a spiral reverse osmosis membrane element using a supply liquid side channel material having a flow rate of from 1.2 times to 1.7 times, and more preferably from 1.2 times to 1.5 times.

Here, X and Y may be satisfied when at least one mesh is focused on, but it is sufficient if at least 10 points of the present invention, preferably an average value obtained by measuring the entire mesh where the supply water passes. Is preferably the interval of the present invention.

If the thickness of the supply liquid side channel material is reduced as described above, the linear velocity of the supply liquid on the film surface increases and the flow on the film surface is disturbed. However, if the thickness of the supply liquid side flow path material is too thin, fouling substances due to impurities or microorganisms in the supply liquid block the flow path on the supply liquid side, and the element performance decreases, This is not preferable because the pressure loss of the element increases, and the power required for the pump for supplying the supply liquid increases, and the element is damaged. Therefore, the average thickness of the supply liquid side channel material is 0.5 mm or more and 1.0 mm or less, preferably 0.5 mm or less.
5 mm or more and 0.9 mm or less, more preferably 0.6 m
m or more and 0.8 mm or less.

The average thickness of the supply liquid side channel material is defined as an average value obtained by measuring at least 10 or more thicknesses of a portion through which the supply water passes with a precision thickness gauge or the like as the average thickness of the present invention. preferable.

In addition, a large variation in the thickness of the supply liquid side flow path material is not preferable because the performance of the reverse osmosis membrane cannot be exerted uniformly, so that the maximum thickness average of the supply liquid side flow path material is not preferable. The thickness is preferably 0.9 times or more and 1.1 times or less.

Further, the material of the supply liquid side channel material is not particularly limited in view of the gist of the present invention, but polyethylene or polypropylene is preferable in terms of not damaging the reverse osmosis membrane and cost.

Further, the above-mentioned permeated liquid flow path material and the supply liquid flow path material of the present invention are combined with a reverse osmosis membrane to have an outer diameter of 200 μm.
mm, the length of 1000 mm, the effective membrane area when incorporated in a spiral-type element having a collecting pipe outer diameter of 32 mm is 25 m ² or more and 35 m ² or less, and preferably 27 m ^2.
Not less than 32 m ² .

The feed liquid supplied to the spiral reverse osmosis membrane element of the present invention has a high impurity concentration and a high osmotic pressure in the solution as in the case of further reverse osmosis separation of seawater or concentrated seawater. A higher solution requires a higher operating pressure, for example, 8 MPa or more, and more preferably 8.5 MPa or more, and furthermore, the element performance is greatly reduced due to concentration polarization, so that the effect of the present invention is sufficiently exhibited and is preferable.

Further, the spiral reverse osmosis membrane element of the present invention can be used in a reverse osmosis membrane separation apparatus in which a supply path is connected to a pump and a reverse osmosis membrane element in this order. In addition, the second reverse osmosis membrane of the reverse osmosis membrane separation device in which the supply flow paths are connected in the order of the first pressure increase pump, the first reverse osmosis membrane element, the second pressure increase pump, and the second reverse osmosis membrane element. Can be used for elements.

[0042]

EXAMPLES The present invention will be described below with reference to specific examples, but the present invention is not limited to these examples. Example 1 and Comparative Example 1 In both the example and the comparative example, 6.0 wt% saline solution was used at 9.0 MPa using a flat membrane evaluation cell having an effective membrane area of 32 cm ^2.
When the reverse osmosis separation is carried out at an operating pressure of
%, With a membrane water production of 0.85 m3 / m2 · d.
Using a 0.15 mm-thick flat cross-linked aromatic polyamide composite membrane, knitted polyester fibers as a woven or knitted fabric constituting a permeate flow path material in a double denbi structure, curing by heat fusion and calendering the surface Single tricots of various thicknesses and nonwoven fabrics of various thicknesses made of polyester staple fiber as the water-permeable fabric, and further, as feed liquid flow path materials, different thicknesses of X and Y are used. Using a polyethylene network structure, each was combined as shown in Table 1, and the outer diameter was 200 mm and the length was 1000 m.
m, an 8 inch diameter spiral reverse osmosis membrane element having a predetermined size and a water collecting pipe diameter of 32 mm was produced. First, the effective membrane area of the element is obtained by dividing the amount of water produced by the element when pure water is subjected to reverse osmosis separation by the pure water permeability coefficient of the reverse osmosis membrane. The salt solution was reverse osmosis-separated under the conditions of a pressure of 9.0 MPa, a salt (NaCl) concentration of 6.0 wt%, a temperature of 25 ° C., a pH of 6.5, and a flow rate of concentrated water of 80 L / min. The amount of water and the element differential pressure were measured, and the results shown in Table 1 were obtained.

It was determined that the desalting rate of the element was 99.7%.
As described above, those having a water production amount of 16.0 m3 / d or more and an element differential pressure of 11.0 kPa or less were evaluated as excellent.
9.5-99.7%, water production 14.0-16.0m3
/ D and the element differential pressure is 11.0 to 14.0 kP
a for those of a, 92.0% to 99.5% for desalination, 12.0 to 14.0 m3 / d for fresh water and 14.0 to 17.0 kPa for element differential pressure. Those having performances other than these were evaluated as x.

The spiral type element using the permeate flow path material and the feed liquid flow path material of the present invention is superior to the element shown in the comparative example under the high pressure and high concentration evaluation conditions. It had element performance.

[0045]

[Table 1]

Example 2, Comparative Example 2 Seawater off Ehime was concentrated by a reverse osmosis membrane separation apparatus using a spiral type reverse osmosis membrane element shown in Table 2 and produced in the same manner as in Example 1 and Comparative Example 1. Is the supply water, the fouling index (FI value) indicating the degree of contamination of the supply water is 3.0 to 4.0, and the operating pressure is 9.0 MP.
a, reverse osmosis separation of concentrated seawater under the conditions of a concentration of evaporation residue of 6.0 wt%, pH of 6.5, and a flow rate of concentrated water of 80 L / min;
After 2,000 hours, the desalting rate of the element, the amount of fresh water, and the differential pressure of the element were measured, and the retention rate from the initial value or the rate of change was obtained.

Here, the retention rate of the desalination rate is (desalination rate after 2000 hours / initial desalination rate) × 100, and the retention rate of water production is (water production after 2000 hours / initial water production). × 100 The change rate of the element differential pressure was determined by (element differential pressure after 2000 hours / initial element differential pressure).

The spiral reverse osmosis membrane element of the present invention has less change in element performance such as desalination rate and fresh water amount even in a long-term evaluation using actual seawater, in comparison with the element shown in the comparative example. In addition, since there is little change in element differential pressure, stable operation can be performed even under high pressure and high concentration conditions.However, the element shown in the comparative example has a drastic change in element performance, and it is difficult to operate stably. there were.

[0049]

[Table 2]

[0050]

According to the present invention, an excellent desalting rate and water production amount can be exhibited even under high-pressure, high-concentration operating conditions, and the pressure loss of the element is small, and the supply water containing dirt components is stable for a long time. It is possible to provide a spiral reverse osmosis membrane element capable of exhibiting improved element performance.

[Brief description of the drawings]

FIG. 1 is a sectional structural view of a spiral reverse osmosis membrane element.

FIG. 2 is a schematic cross-sectional view showing a typical conventional permeate flow path material.

FIG. 3 is a schematic cross-sectional view of a permeate flow path material used in a conventional spiral element used under high pressure.

FIG. 4 is a schematic cross-sectional view of the structure of the supply liquid channel material of the present invention.

FIG. 5 is a conceptual diagram showing the structure of a supply liquid channel material.

FIG. 6 is a conceptual diagram showing a structure of a supply liquid flow path material and a flow of a supply liquid.

FIG. 7 is a conceptual diagram showing the structure of the supply liquid flow path material and the flow of the supply liquid according to the present invention.

[Explanation of symbols]

 1: Reverse osmosis membrane 2: Permeate liquid side flow path material 3: Supply liquid side flow path material 4: Water collecting hole 5: Water collecting pipe 6: Groove 7: Convex part 8: Small hole 9: Porous sheet 10: Woven and knitted fabric 11: Water-permeable cloth 12: Y of supply liquid channel material 13: X of supply liquid channel material 14: Angle (α) of mesh of supply liquid channel material

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-54-31087 (JP, A) JP-A-60-41505 (JP, A) JP-A-5-168869 (JP, A) (58) Field (Int. Cl. ⁷ , DB name) B01D 63/10 WPI (DIALOG)

Claims (6)

(57) [Claims] 1. Two reverse osmosis membranes are partially joined to each other,
The inside of the two reverse osmosis membranes is the permeate side, the outside of the two reverse osmosis membranes is the supply side, the permeate side is disposed on the permeate side, and the supply side channel is on the supply side. In a spiral reverse osmosis membrane element formed by winding a unit provided with a perimeter around a water collection pipe, the permeated liquid flow path material has a plurality of grooves on at least one surface, and has an average thickness of 0.15 mm or more. 0.4
mm or less, and a water-permeable cloth having an average thickness of 0.05 mm or more and 0.2 mm or less, which is disposed on the surface of the woven or knitted material having a groove. And the mesh X of this stitch has an interval X between intersections in a direction perpendicular to the axis of the water collecting pipe of 2 mm.
A spiral type reverse osmosis membrane element, wherein the distance Y between the intersections in the axial direction is not less than 1.0 times and not more than 1.8 times X. 2. A method for producing a liquid, comprising using the spiral reverse osmosis membrane element according to claim 1. 3. The method for producing a liquid according to claim 2, wherein the operating pressure is 8 MPa or more. 4. The method for producing a liquid according to claim 2, wherein seawater is used as the liquid. 5. A reverse osmosis membrane separation device comprising a pump and a spiral reverse osmosis membrane element according to claim 1 connected in this order. 6. A reverse osmosis membrane comprising a first booster pump, a reverse osmosis membrane element, a second booster pump and the spiral reverse osmosis membrane element according to claim 1 connected in this order. Separation device.