JPWO2020080428A1 - Separation membrane module and its operation method - Google Patents

Abstract

The present invention includes a central tube, a plurality of separation membrane elements having a separation membrane surrounded by the center tube, and telescope prevention plates provided at both ends in the longitudinal direction of the center tube, a cylindrical pressure vessel, and a cylindrical pressure vessel. When at least one sealing member is provided, the sealing member closes a part of the gap between the pressure vessel and the separation membrane element, and the sealing member is observed from the longitudinal direction of the pressure vessel. The closure rate of the gap is 60% or less in at least one sealing member, and the longitudinal direction of the pressure vessel and the longitudinal direction of the separation membrane element are matched so that the plurality of separation membrane elements have the pressure. It relates to a separation membrane module that is inserted into a vessel and connected in series.

Description

The present invention relates to a separation membrane module and an operation method thereof.

In recent years, fluid separation techniques using various separation membranes such as reverse osmosis membranes, nanofiltration membranes, ultrafiltration membranes or microfiltration membranes have been developed. For example, the reverse osmosis separation method using a reverse osmosis membrane is seawater. It is widely applied to the desalination of brackish water, the production of ultrapure water, and the concentration and recovery of valuable resources.

A common problem in fluid separation using a separation membrane is fouling, in which impurities contained in the fluid to be treated are adsorbed or deposited on the surface of the separation membrane or the like to deteriorate the separation membrane performance. Although the separation membrane in which fouling has occurred can be recovered by washing with a chemical solution, the treatment causes many problems such as a decrease in the operating rate due to the suspension of the fluid separation operation and deterioration of the separation membrane due to the influence of the chemical solution. It accompanies.

The flat membrane-like separation membrane is generally used in the form of a spiral separation membrane element in which the separation membrane is surrounded by a central canal having pores, and this spiral separation membrane element is particularly fau. It is known that rings are likely to occur. And the spiral type separation membrane element is often used by connecting a plurality of them in series. In particular, when the fluid to be treated is seawater, the occurrence of fouling in the first-stage spiral separation membrane element having a low osmotic pressure and a large permeation flux becomes remarkable.

When fouling occurs in the spiral separation membrane element, the flow path inside the spiral separation membrane element is blocked, and the internal members are deformed or extruded, causing a phenomenon called telescope in which the separation performance is significantly reduced. Is done.

In order to suppress this telescope, there is a technique (Patent Documents 1 to 3) that temporarily switches the flow direction of the fluid to be treated in the spiral separation membrane element to the opposite side and flushes the substance deposited on the separation membrane surface. Are known.

International Publication No. 2009/128328 Japanese Patent Application Laid-Open No. 2004-141846 Japanese Patent Application Laid-Open No. 2002-210335

However, in the conventional technique, it has been regarded as a problem that the telescope cannot be effectively suppressed when the flushing timing is inappropriate due to, for example, a change in the water quality of the water to be treated.

Therefore, an object of the present invention is to provide a separation membrane module capable of effectively suppressing the telescope of the separation membrane element, which is a component of the separation membrane module, without increasing the frequency of chemical washing. ..

In order to achieve the above object, in the present invention, with a plurality of separation membrane elements having a central tube, a separation membrane surrounded by the central tube, and telescope prevention plates provided at both ends in the longitudinal direction of the central tube. A cylindrical pressure vessel and at least one sealing member are provided, and the sealing member closes a part of the gap between the pressure vessel and the separation membrane element, and the sealing member is pressed against the pressure. The closure rate of the gap when observed from the longitudinal direction of the vessel is 60% or less in at least one sealing member, and the longitudinal direction of the pressure vessel and the longitudinal direction of the separation membrane element are made to coincide with each other. Provided is a separation membrane module in which the separation membrane element of the above is inserted into the pressure vessel and connected in series.

In order to achieve the above object, in another aspect of the present invention, a plurality of telescope prevention plates having a central tube, a separation film surrounded by the central tube, and telescope prevention plates provided at both ends in the longitudinal direction of the central tube. A plurality of the separating membrane elements are provided by comprising a separating membrane element, a cylindrical pressure vessel, and at least one sealing member, and matching the longitudinal direction of the pressure vessel with the longitudinal direction of the separating membrane element. It is inserted into the pressure vessel and connected in series, and the difference between the minimum inner diameter of the pressure vessel and the maximum outer diameter of the separation membrane element is 0.1 to 1.8 mm, and the sealing member. However, a part of the gap between the pressure vessel and the separation membrane element is closed, and the closing rate of the gap when the sealing member is observed from the longitudinal direction of the pressure vessel is at least one sealing member. 60% or less, and the minimum area when observing the gap formed between the telescope prevention plates of the separation membrane element adjacent to each other from the direction perpendicular to the longitudinal direction of the pressure vessel. S1 _n , a communication flow path formed in the telescope prevention plate for communicating the gap between the pressure vessel and the separation membrane element and the inside of the separation membrane element is provided in the longitudinal direction of the pressure vessel. when observed from a vertical direction when the minimum area S2 _n, and the sum of the values of the S1 _n and S2 _n is at 1800 mm ² or more, to provide a separation membrane module.

According to the present invention, the space existing between the pressure vessel and the separation membrane element serves as a bypass flow path, and even when the pressure loss of the separation membrane element increases, the generation of the telescope is suppressed. It becomes possible.

Further, it is possible to more accurately determine the timing at which the separation membrane element should be washed with the chemical solution by using the amount and properties of the fluid to be treated in the so-called bypass flow path as an index.

FIG. 1 is a partially cutaway perspective view showing one aspect of the separation membrane element included in the separation membrane module of the present invention. FIG. 2 is a schematic view showing an example of an embodiment of the separation membrane module of the present invention. FIG. 3 is a schematic view showing an example of an embodiment of the separation membrane module of the present invention. FIG. 4 is a schematic view showing an example of the shape of the through hole or the communication groove provided in the seal member. FIG. 5 is a schematic view showing one aspect of the telescope prevention plate constituting the separation membrane element included in the separation membrane module of the present invention. FIG. 6 is a schematic view showing an example of an embodiment of the separation membrane module of the present invention. FIG. 7 is a schematic view showing an example of an embodiment of the separation membrane module of the present invention. 8 (a) and 8 (b) are schematic views showing aspects of a telescope prevention plate and a spacer constituting the separation membrane element provided in the separation membrane module of the present invention. FIG. 9 is a schematic view showing an example in which a C-type split ring seal is used as the seal member. FIG. 10 is a schematic view showing an example of the shape of the through hole or the communication groove provided in the seal member. 11 (a) to 11 (c) are schematic views showing an example of the shape of the through hole or the communication groove provided in the seal member.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, but the present invention is not limited thereto.

The separation membrane module of the present invention has a central canal, a separation membrane surrounded by the central canal, and a plurality of separation membrane elements having telescope prevention plates provided at both ends in the longitudinal direction of the central canal, and a cylindrical shape. Pressure vessel and at least one sealing member.

1. 1. Separation Membrane Element FIG. 1 is a partially cutaway perspective view showing an example of an embodiment of the separation membrane element included in the separation membrane module of the present invention.

In the separation membrane element 20 in this embodiment, the separation membrane 21 is surrounded by a perforated central tube 24, and the outer surface of the surrounding body is covered with an exterior material (not shown). There is. Further, telescope prevention plates 25 are provided at both ends of the winding body in the longitudinal direction for the purpose of preventing telescope. A circumferential groove 251 is formed on the outer peripheral surface of the telescope prevention plate 25 for fitting and fixing a seal member described later.

Examples of the material of the perforated central canal constituting the separation membrane element include resin and metal, but from the viewpoint of cost and durability, resin such as noryl resin or ABS resin is preferable.

Examples of the separation membrane constituting the separation membrane element include a reverse osmosis membrane, an ultrafiltration membrane, a microfiltration membrane, a gas separation membrane, and a degassing membrane.

The outer surface of the surrounding body constituting the separation membrane element may be covered with an exterior material. Examples of the exterior material include a polyester, polypropylene, polyethylene or polyvinyl chloride film, or a glass fiber sheet coated with a curable resin.

Examples of the material of the telescope prevention plate constituting the separation membrane element include a thermoplastic resin, a thermosetting resin, and a heat-resistant resin. As for the shape of the telescope prevention plate, in order to supply the supplied fluid to the inside of the separation membrane element with high efficiency while maintaining the strength, the outer peripheral annular member and the inner peripheral annular member are connected by a plurality of spoke-shaped members. , Spoke type structure is preferable.

The fluid to be processed, that is, the supply fluid 26 is supplied to the separation membrane element 20 from one end in the longitudinal direction thereof. A part of the supply fluid 26 permeates the separation membrane 21 inside the separation membrane element 20, is collected inside the central tube through the hole of the central tube, and is recovered as a permeation fluid 27 from the other end of the separation membrane element 20. Further, the concentrated fluid 28 that has not penetrated the separation membrane 21 is also discharged from the other end of the separation membrane element 20.

In order to form the fluid flow as described above, a part of the end portion of the separation membrane 21 is sealed so that the supply fluid 26 and the permeation fluid 27 are not mixed. Examples of the means for sealing the end portion of the separation film include an adhesive method, and examples of the adhesive used in the adhesive method include urethane-based adhesives, epoxy-based adhesives, and hot-melt adhesives.

As shown in FIG. 1, a supply-side flow path material 23 and a permeation-side flow path material 22 for forming a fluid flow path may be arranged between the surfaces of the facing separation membranes.

Examples of the supply side flow path material and the transmission side flow path material include a net-like member, a mesh-like member, a grooved sheet, and a corrugated sheet.

2. Separation Membrane Module In the separation membrane module of the present invention, a plurality of separation membrane elements are inserted into the pressure vessel and in series by matching the longitudinal direction of the cylindrical pressure vessel with the longitudinal direction of the separation membrane element. Must be connected.

FIG. 2 is a schematic view showing an example of an embodiment of the separation membrane module of the present invention.

In the separation membrane module 47 in this embodiment, the longitudinal direction of the cylindrical pressure vessel 46 and the longitudinal direction of the separation membrane elements 39a to 39f are matched with each other, and the six separation membrane elements (39a, 39b, 39c, 39d) are aligned. , 39e, 39f) are inserted into the pressure vessel and connected in series. Here, "connected in series" means that the central canal of one separation membrane element and the central canal of another (one) separation membrane element adjacent to each other are connected from the central canal of one separation membrane element. A mode in which all of the outflowing permeated fluid flows into the central canal of another (one) separation membrane element adjacent to it. In FIG. 2, the six separation membrane elements 39a to 39f are connected in series by connecting the central tubes of the separation membrane elements 39a to 39f with the central tube connector 41, respectively. Further, one central tube of the separation membrane element 39a and the separation membrane element 39f located at both ends of the separation membrane module 47 is connected to the permeation fluid outlets 43a and 43b, respectively.

In the separation membrane module 47 shown in FIG. 2, the supply fluid is supplied to the end portion of the separation membrane element 39a via the supply fluid supply port 38. The concentrated fluid separated by the separation membrane element 39a is supplied to the separation membrane element 39b. After that, the concentrated fluid is sequentially supplied to the separation membrane elements 39c, 39d, 39e and 39f, separated, and then discharged from the concentrated fluid discharge port 40.

In the separation membrane module of the present invention, the difference between the minimum inner diameter of the pressure vessel and the maximum outer diameter of the separation membrane element is preferably 0.1 to 1.8 mm. By ensuring a gap of at least 0.1 to 1.8 mm between the pressure vessel and the separation membrane element, the gap functions as a bypass flow path. For example, even if the flow path inside the separation membrane element is blocked due to the occurrence of fouling and the flow resistance increases, a part of the supply fluid is released to this bypass flow path to allow the telescope of the separation membrane element to be released. It becomes possible to deter.

If the difference between the minimum inner diameter of the pressure vessel and the maximum outer diameter of the separation membrane element is less than 0.1 mm, not only is it difficult to insert the separation membrane element into the pressure vessel, but also the pressure vessel and the separation membrane element The gap does not function as a bypass flow path. On the other hand, if the above difference exceeds 1.8 mm, the amount of supply fluid supplied to the separation membrane element may be excessively reduced. Furthermore, when the separation membrane module is installed in the horizontal direction, for example, the sealing member located below the separation membrane element is crushed by gravity, causing unevenness in the flow of the supply fluid that has escaped to the bypass flow path. As a result, the separation performance of the separation membrane module deteriorates.

The difference between the minimum inner diameter of the pressure vessel and the maximum outer diameter of the separation membrane element is preferably 0.5 to 1.5 mm, more preferably 0.5 to 1.0 mm.

The minimum inner diameter of the pressure vessel and the maximum outer diameter of the separation membrane element can be measured using a caliper or the like. When the maximum outer diameter differs between the plurality of separation membrane elements, the above difference shall be calculated by using the value of the largest maximum outer diameter as the "maximum outer diameter of the separation membrane element".

For the separation membrane element that is most likely to generate a telescope with the most feed fluid (in the longitudinal direction of the pressure vessel) on the feed fluid supply port side, it escapes to the bypass flow rate, which accounts for the total flow rate of the feed fluid. The ratio of the flow rate of the fluid to be used is preferably 10 to 60%, more preferably 20 to 50%, from the viewpoint of sufficiently reducing the flow resistance inside the separation membrane element.

In addition, when there is no gap between the telescope prevention plates between the separation membrane element and other adjacent separation membrane elements in the longitudinal direction of the pressure vessel, and the separation membrane elements are in contact with each other. For example, when the telescope prevention plates of the separation membrane elements are in close contact with each other, not only is it difficult for the fluid that has once escaped to the bypass flow path to be supplied to the inside of the separation membrane element again. It becomes difficult to suppress the pressure loss within an appropriate range. Therefore, in such a case, for example, as shown in FIG. 5, it is necessary to provide the telescope prevention plate 25 with communication flow paths 64a to 64n for communicating the bypass flow path and the inside of the separation membrane element.

3. 3. Sealing member In the separation membrane module of the present invention, the sealing member closes a part of the gap between the pressure vessel and the separation membrane element, and the gap when the sealing member is observed from the longitudinal direction of the pressure vessel. The blockage rate of at least one sealing member needs to be 60% or less. When the blockage rate is 60% or less, the ratio of the fluid that escapes to the bypass flow path to the total flow rate of the supply fluid becomes a preferable ratio. If the blockage rate is more preferably less than 40%, still more preferably less than 30%, a greater effect can be obtained.

In the separation membrane module 47 shown in FIG. 2, a plurality of sealing members 45a1 to 45f1 and sealing members 45a2 to 45f2 fill a gap between the telescope prevention plates provided at both ends of the separation membrane elements 39a to 39f and the pressure vessel. It is blocked.

The sealing member appropriately closes the gap between the pressure vessel and the separation membrane element, that is, the bypass flow path, and adjusts the amount of the supply fluid that escapes to the bypass flow path, so that the separation efficiency of the entire separation membrane module is excessively reduced. It plays a role in preventing.

Examples of the sealing member include known U-coupling seals, V-coupling seals, O-ring seals or split ring seals. Here, the split ring seal has a shape in which an annular member is cut at one or more places. The radial cut surface of the annular split ring seal is preferably rectangular so that the gap is closed in a symmetrical shape between the pressure vessel and the separation membrane element. As a result, the supply fluid can be supplied from either end of the separation membrane module of the present invention, and the separation membrane element can be easily moved in the pressure vessel.

The material of the sealing member is not particularly limited as long as it has durability against the supplied fluid. The material of the U-coupling seal, the V-coupling seal or the O-ring seal is preferably an elastic material from the viewpoint of ease of installation, and the material of the split ring seal is preferably an inelastic material.

Examples of the elastic material include rubbers such as nitrile rubber, styrene rubber, silicone rubber, fluororubber, acrylic rubber, ethylene propylene rubber and urethane rubber. Examples of the method for cross-linking these rubbers include vulcanization using sulfur as a vulcanizing agent or a cross-linking reaction using a peroxide. A cross-linking reaction using oxide is preferable.

Examples of the inelastic material include resins such as polytetrafluoroethylene, polyvinylidene fluoride, polyethylene and polypropylene, metals such as iron, stainless steel, copper, aluminum and titanium or alloys thereof, ceramics, graphite, asbestos and FRP. Examples include organic-inorganic composites.

When the sealing member is observed from the longitudinal direction of the pressure vessel, the closing rate of the gap between the pressure vessel and the separation membrane element needs to be 60% or less in at least one sealing member. When the blockage rate is 60% or less, the gap between the pressure vessel and the separation membrane element can be fully utilized as a bypass flow path. If the blockage rate is more preferably less than 40%, still more preferably less than 30%, a greater effect can be obtained.

The closing rate of the gap between the pressure vessel and the separation membrane element is determined by taking a photograph of the pressure vessel, the separation membrane element and the sealing member from the longitudinal direction of the pressure vessel, and from the image, the area H1 of the gap between the pressure vessel and the separation membrane element. , And the total area H2 of the portion closed by the gap is determined, and H2 is divided by H1 and expressed as a percentage. If the value of H1 or H2 determined by observing from one side in the longitudinal direction of the pressure vessel is different from the value of H1 or H2 determined by observing from the other side in the longitudinal direction of the pressure vessel, they are averaged. The value can be used to calculate the blockage rate described above.

As a means for adjusting the blocking rate to a suitable value, for example, as shown in FIG. 3, a through hole 61a or 61b is provided in a part of the sealing member so as to penetrate the sealing member in the longitudinal direction of the pressure vessel. A method or a method of providing a communication groove 62a or 62b on the outer surface of the sealing member or the inner surface of the pressure vessel for allowing a part of the supply fluid to escape to the bypass flow path can be mentioned.

The shape of the through hole or the communication groove provided in a part of the seal member is not particularly limited, and examples thereof include various shapes as shown in FIG. 4 by taking a split ring seal as an example. In this way, even when the flow resistance increases due to, for example, the flow path inside the separation membrane element being blocked, the telescope of the separation membrane element can be suppressed by letting a part of the supply fluid escape to the bypass flow path. It will be possible.
Since the separation membrane module is configured so that more supply fluid flows into the bypass flow path 60 as the flow resistance inside the separation membrane element increases, the seal member is an O-ring seal made of an elastic material or the like. In some cases, it is preferable that the shape of the through hole is a star-shaped polygon or a slit that can be flexibly deformed, or that a part of the sealing member is thinned.

When the sealing member is observed from the longitudinal direction of the pressure vessel, the closing rate of the gap between the pressure vessel and the separation membrane element may be 60% or less at at least one sealing member site, but the sealing member is sealed in the pressure vessel. When there are a plurality of members, the blockage rate is preferably 60% or less on at least one side (supply fluid supply port side) of the seal members located at both ends in the longitudinal direction of the pressure vessel, and the parts of the other seal members. In, for example, the gap may be in a state of complete occlusion (occlusion rate 100%). However, when there are a plurality of sealing members in one separation membrane element, it is desirable that the sealing rate of all the sealing members of the separation membrane element on the supply fluid supply port side is 60% or less.

When the seal member is fitted into the circumferential groove 251 of the telescope prevention plate, the through hole or communication groove of the seal member is formed between the telescope prevention plate and the pressure vessel in order to allow the supply fluid to escape to the bypass flow path while maintaining the strength of the seal member. It is desirable that the seal member is located between the two, and as shown in FIGS. 10 and 11, a through hole or a communication groove is formed from the outer diameter of the circle having an intermediate diameter between the outer diameter 111 and the inner diameter 110 of the seal member. desirable. Further, when the seal member is attached to the circumferential groove of the telescope prevention plate and observed from the longitudinal direction of the pressure vessel, a through hole or a communication groove of the seal member is formed in a portion outside the diameter of the separation membrane element. Is desirable. Further, when the distribution of the through hole or the communication groove of the seal member is close to the sparse portion 112 in the circumferential direction of the seal, the weight of the separation membrane element is applied to the seal member, so that the through hole or the communication groove of the seal member is applied. By installing the part where the distribution is sparse in the vertical direction downward, it is possible to prevent the sealing member from being deformed, the separation membrane element can be fixed to the center of the pressure vessel, and it is possible to prevent the supply fluid from being biased. Become. As described above, the weight of the separation membrane element is applied to the seal member downward in the vertical direction, and it is sufficient that the seal strength is strong only in the portion below the vertical direction. It is desirable that the sparse portion 112 in the direction is 30% or less of the entire seal.

Here, if the distribution of through holes or communication grooves of the seal member is sparse or dense, the seal member is divided into 10 equal parts in the circumferential direction of the seal member, and the blockage rate of each portion is larger than the blockage rate of the entire seal member. If it is small, it is defined as "sparse", and if it is small, it is defined as "dense".

As shown in FIG. 9, the supply fluid can be released to the bypass flow path by the C-shaped split ring seal formed from a part of the ring.
It is desirable that the angle 103 formed between both ends and the center of the seal is larger than 144 °, more preferably larger than 216 °, and even more preferably larger than 252 ° for the defective portion of the C-type split ring seal to obtain a greater effect. ..

However, when a C-type split ring seal is used, it is preferable that the angle 103 formed between both ends of the C-type split ring seal and the center of the seal is smaller than 180 °. As a result, even if the separation membrane element moves due to vibration, it is fixed to the C-type split ring seal, and the distance between the pressure vessel and the separation membrane element can be maintained.

In the longitudinal direction of the pressure vessel, the separation membrane element that exists closest to the supply fluid supply port has a large flow rate of the supply fluid and is easy to capture impurities such as fine particles that cause fouling, so the telescope is the most suitable. It is likely to occur. Therefore, at least at the site of the seal member most present on the supply fluid supply port side, the above-mentioned blockage rate is preferably 60% or less, more preferably less than 40%, and further preferably less than 30%. Great effect can be obtained. That is, in the longitudinal direction of the pressure vessel, the closure rate B1 at the portion of the seal member located at one end is preferably 60% or less, more preferably less than 40%, still more preferably less than 30%. The effect is obtained.

In the longitudinal direction of the pressure vessel, the separation membrane element existing on the other end side of the separation membrane element existing on the supply fluid supply port side is less likely to generate a telescope. Therefore, in the longitudinal direction of the pressure vessel, the blockage rate B2 of the seal member adjacent to the seal member closest to the supply fluid supply port side may be larger than the blockage rate B1. That is, in the longitudinal direction of the pressure vessel, the blockage rate B1 is 60% or less at the portion of the seal member located at one end, and the blockage rate B2 in the seal member adjacent thereto is B1 <B2. It is more preferable to satisfy the relationship of.

In order to increase the energy efficiency of separation, the blockage rate B2 is preferably 80% or more, and more preferably 90% or more.

Further, in the longitudinal direction of the pressure vessel, the seal member located at one end of the pressure vessel has a closure rate B1 of 60% or less, and the seal member located at the other end has the closure rate. It is more preferable that Bn is high. Here, the blockage rate Bn means the blockage rate at the site of the nth seal member from the seal member located at one end in the longitudinal direction of the pressure vessel.

On the other hand, in order to prevent a part of the supply fluid from being discharged from the concentrated fluid discharge port without passing through the separation membrane element at all, when there are a plurality of sealing members, it is closest to the supply fluid supply port side. The above-mentioned closure rate of at least one seal member portion other than the existing seal member is preferably 100%, and the above-mentioned occlusion rate of the seal member portion most present on the concentrated fluid discharge port side is 100%. More preferably. Further, as a result, the balance between the amount of permeated fluid flowing out from the separation membrane element on the supply fluid supply port side and the amount of permeation fluid flowing out from the separation membrane element on the concentrated fluid discharge port side becomes a suitable balance, and the permeation obtained as a whole is obtained. The quality of the fluid can be improved.

Further, in the separation membrane module of the present invention, the total value of _{S1 n} and S2 _n ^{is preferably 1800 mm 2} or more.

Here, S1 _n means the minimum area when the gap formed between the telescope prevention plates of the adjacent separation membrane elements is observed from the direction perpendicular to the longitudinal direction of the pressure vessel. Further, S2 _n means that the communication flow path formed in the telescope prevention plate for communicating the gap between the pressure vessel and the separation membrane element and the inside of the separation membrane element is perpendicular to the longitudinal direction of the pressure vessel. The minimum area when observed from the direction.

When three or more separation membrane elements are connected in series in the pressure vessel, a _{plurality of S1 n} exist (S1 ₁ , S1 ₂ ...). Further, when a plurality of communication flow paths are formed in at least a part of the telescope prevention plates in the entire plurality of separation membrane elements included in the separation membrane module, there are a plurality of S2 _n (S2 ₁ , S2 _{2, ...}・ ・) It will be. For S1 _n and S2 _n , the total value of all of them ^{may be 1800 mm 2} or more, _{and either S1 n} or S2 _n may be 0 (zero).

When the total value of _{S1 n} and S2 _n ^{is 1800 mm 2} or more, the pressure loss can be suppressed to an appropriate range in the configuration of the separation membrane module of the present invention. The total value of S1 _n and S2 _n ^{is preferably 2500 mm 2} or more, and more preferably 2800 mm ² or more. On the other hand, _if the total value of _{S1 n} and S2 ^{n exceeds 12000 mm 2} , the pressure loss does not increase. Therefore, the total value of _{S1 n} and S2 _n ^{is preferably 12000 mm 2} or less.

The values of S1 _n and S2 _n , respectively, indicate that the plurality of separation membrane elements that have not been inserted into the pressure vessel are connected in series from the direction perpendicular to the longitudinal direction of the pressure vessel to the entire circumference. It is possible to observe, take a picture at a position where each value is the minimum, and determine from the image.

As a method of forming a gap between the telescope prevention plates of the adjacent separation membrane elements, as shown in FIG. 7, a method of providing a central canal connector 80 or a spacer 81 between the adjacent separation membrane elements is provided. Can be mentioned. Only one of the central canal connector and the spacer may be provided. The spacer may be integrated with the central canal connector as in the spacer 92 shown in FIG. 8 (a), or may have a diameter larger than that of the telescope prevention plate as in the spacer 91 shown in FIG. 8 (b). It may be small or ring-shaped.

4. Operation method of separation membrane module In the operation method of the separation membrane module of the present invention, the supply fluid is separated into a permeation fluid and a concentrated fluid by using the separation membrane module of the present invention.

When the flow resistance of the separation membrane module of the present invention increases due to blockage of the flow path inside the separation membrane element, the amount of fluid that escapes to the bypass flow path, which is the gap between the pressure vessel and the separation membrane element, increases. To increase. A change in the amount of fluid escaping to such a bypass flow path may be detected. For example, when the value exceeds a preset threshold value, the amount of supply fluid supplied to the separation membrane module is reduced (for example). It is possible to prevent the telescope of the separation membrane element by means such as reducing the pressure of the feed fluid), cleaning the separation membrane element, or replacing the separation membrane element.

As a method of detecting a change in the amount of fluid escaping to the bypass flow path, for example, a method of providing a means capable of generating aerodynamic noise such as a whistle in the bypass flow path, or a method of measuring an electromotive force generated by electromagnetic induction. Can be mentioned.

As shown in FIG. 6, an intermediate plug 70 is provided between the adjacent separation membrane elements instead of the central tube connector 41, and a permeated fluid outlet (43a, By providing each of the 43b), for example, the permeated fluid around the intermediate plug 70 can be individually sampled from each permeated fluid outlet.

In this case, it is also possible to analyze the degree of blockage inside the separation membrane element by measuring and comparing the flow rate or properties of the permeated fluid before and after the intermediate plug. Specifically, when the inside of the separation membrane element on the supply fluid supply port side of the intermediate plug is closed, the flow rate of the fluid before the intermediate plug decreases and the electrical conductivity of the permeated fluid increases.

In addition to electrical conductivity, examples of the properties of the permeated fluid include total dissolved solids (TDS). The electrical conductivity can be measured using an online or handy type electrical conductivity meter. Further, total dissolved solids (TDS) can be calculated by heating and evaporating the sampled permeated fluid and measuring the mass of the residue.

The intermediate plug is preferably provided between the separation membrane element located at one end and the separation membrane element adjacent thereto in the longitudinal direction of the pressure vessel. By setting the side where the intermediate plug is provided as the supply fluid supply port side, the separation membrane element that is most likely to generate the telescope (in the longitudinal direction of the pressure vessel) and is present on the supply fluid supply port side. The degree of obstruction can be analyzed.

Further, by appropriately adjusting the supply fluid so that the flow rate of the permeated fluid in front of the intermediate plug does not exceed the threshold value, it is possible to more effectively suppress the blockage inside the separation membrane element. Above all, when the temperature of the water to be treated is high or when the separation membrane element is new, the possibility of telescope generation increases, so more supply fluid is released to the bypass flow path and in front of the intermediate plug. By reducing the flow rate of the fluid in the above, the telescope can be suppressed more effectively.

Examples of the supply fluid used in the operation method of the separation membrane module of the present invention include river water, seawater, treated sewage water, rainwater, industrial water or industrial wastewater, but the possibility of telescope generation is higher. The method of operating the separation membrane module of the present invention is particularly suitable for a feed fluid containing an organic substance or an inorganic substance, or a feed fluid having an osmotic pressure of 20 bar or more.

(Example 1)
Two separation membrane elements (manufactured by Toray Industries, Inc .; Romenbra (registered trademark) TM820V-400) in which a separation membrane is wound around the central canal and telescope prevention plates are provided at both ends in the longitudinal direction are prepared, and the central canal is prepared. They were connected in series with an adhesive and inserted into a pressure vessel. The difference between the minimum inner diameter of the pressure vessel and the maximum outer diameter of the separation membrane element was 0.9 mm. The gap between the separation membrane element on the supply fluid supply port side of the pressure vessel and the pressure vessel was partially closed with a nitrile rubber U-coupling seal provided with a through hole as a sealing member. The blockage rate of the seal member was 60%. The value of _{S1 n} for the gap formed between the telescope prevention plates of the adjacent separation membrane elements ^{was 1800 mm 2} . Using the separation membrane module produced in this manner, a NaCl aqueous solution having a concentration of 32000 mg / L, which is a supply fluid, is separated into a permeated fluid and a concentrated fluid under the conditions of a ^{recovery rate of 8% and a supply amount of 15 m 3 / h.} As a result of the operation, the differential pressure between the supply pressure of the NaCl aqueous solution to the separation membrane module and the concentrated water pressure was 0.08 kgf / cm ² .

(Example 2)
When a separation membrane module was manufactured in the same manner as in Example 1 and operated under the same conditions except _{that the value of S1 n} was set to 2500 mm ^{2 , the differential pressure was 0.075 kgf / cm 2} .

(Example 3)
When the separation membrane module was manufactured in the same manner as in Example 1 and operated under the same conditions except that the closure rate of the seal member was set to 30%, the differential pressure was 0.055 kgf / cm ² .

(Example 4)
When the separation membrane module was manufactured in the same manner as in Example 1 and operated under the same conditions except that the closure rate of the seal member was set to 40%, the differential pressure was 0.060 kgf / cm ² .

(Comparative Example 1)
When the separation membrane module was manufactured in the same manner as in Example 1 and operated under the same conditions except that the closure rate of the seal member was set to 80%, the differential pressure was as high as ^{0.31 kgf / cm 2.} ..

(Comparative Example 2)
When a separation membrane module was manufactured in the same manner as in Example 1 and operated under the same conditions except _{that the value of S1 n} was set to 1600 mm ² , the differential pressure was as high as ^{0.15 kgf / cm 2.}

(Comparative Example 3)
When the separation membrane module was manufactured in the same manner as in Example 1 and operated under the same conditions except that the closure rate of the seal member was set to 70%, the differential pressure was as high as ^{0.19 kgf / cm 2.} ..

This application is based on Japanese Patent Application 2018-195536 filed on October 17, 2018, the contents of which are incorporated herein by reference.

20: Separation membrane element 21: Separation membrane 22: Permeation side flow path material 23: Supply side flow path material 24: Central canal 25: Telescope prevention plate 251: Circumferential groove 26, 26a: Supply fluid (supply water)
27, 27a: Permeated fluid (permeated water)
28: Concentrated fluid (concentrated water)
38: Supply fluid supply port 39a, 39b, 39c, 39d, 39e, 39f: Separation membrane element 40: Concentrated fluid discharge port 41: Central tube connector 42a, 42b: End plate 43a, 43b: Permeate fluid outlet 45a1, 45b1, 45c1, 45d1, 45e1, 45f1: Sealing member 45a2, 45b2, 45c2, 45d2, 45e2, 45f2: Sealing member 46: Pressure vessel 47: Separation membrane module 60: Bypass flow path 61a, 61b: Through hole 61r to 61z: Through hole Or communication groove 62a, 62b: Communication groove 64a to 64n: Communication flow path 70: Intermediate plug 80: Central tube connector 81: Spacer 82: Telescope prevention plate 91: Ring-shaped spacer 92: Spacer 100 integrated with the central tube connector : C-type split ring seal 103: Angle formed by both ends and the center of the seal 110: Inner diameter of the seal 111: Outer diameter of the seal 112: Area where the communication groove is sparsely distributed

Claims (26)

A plurality of separation membrane elements having a central canal, a separation membrane surrounded by the central canal, and telescope prevention plates provided at both ends of the central canal in the longitudinal direction.
Cylindrical pressure vessel and
With at least one sealing member,
A plurality of the separation membrane elements are inserted into the pressure vessel and connected in series by matching the longitudinal direction of the pressure vessel with the longitudinal direction of the separation membrane element.
The difference between the minimum inner diameter of the pressure vessel and the maximum outer diameter of the separation membrane element is 0.1 to 1.8 mm.
The sealing member closes a part of the gap between the pressure vessel and the separation membrane element.
When the sealing member is observed from the longitudinal direction of the pressure vessel, the closing rate of the gap is 60% or less in at least one sealing member.
When the gap formed between the telescope prevention plates of the separation membrane element adjacent to each other is observed from a direction perpendicular to the longitudinal direction of the pressure vessel, the minimum area is S1 _n .
The communication flow path formed in the telescope prevention plate for communicating the gap between the pressure vessel and the separation membrane element and the inside of the separation membrane element is in a direction perpendicular to the longitudinal direction of the pressure vessel. When the minimum area when observed from is S2 _n ,
A separation membrane module in which the total value of _{S1 n} and S2 _n ^{is 1800 mm 2 or more.} With a plurality of the sealing members
When the sealing member located at one end in the longitudinal direction of the pressure vessel is observed from the longitudinal direction of the pressure vessel, the closure rate B1 of the gap between the pressure vessel and the separation membrane element is 60% or less. Yes and
When the seal member adjacent to the seal member located at one end is observed from the longitudinal direction of the pressure vessel, the closing rate B2 of the gap between the pressure vessel and the separation membrane element has a relationship of B1 <B2. The separation membrane module according to claim 1, wherein the separation membrane module is satisfied. The separation membrane module according to claim 2, wherein the blockage rate B2 of the gap is 80% or more. With a plurality of the sealing members
When the sealing member located at one end in the longitudinal direction of the pressure vessel is observed from the longitudinal direction of the pressure vessel, the closure rate B1 of the gap between the pressure vessel and the separation membrane element is 60% or less. Yes and
The seal member located on the other end side of the seal member located at one end has a higher blockage rate Bn of the gap between the pressure vessel and the separation membrane element when observed from the longitudinal direction of the pressure vessel. The separation membrane module according to any one of claims 1 to 3. The separation membrane module according to claim 4, wherein the blockage rate Bn is 100% for at least one of the sealing members. An intermediate plug is provided between one of the separation membrane elements and the separation membrane element adjacent thereto.
The separation membrane module according to any one of claims 1 to 5, wherein in the longitudinal direction of the pressure vessel, permeation fluid outlets are provided on both sides of the intermediate plug. The separation membrane module according to claim 6, wherein the intermediate plug is provided between the separation membrane element located at one end in the longitudinal direction of the pressure vessel and the separation membrane element adjacent thereto. The separation according to any one of claims 1 to 7, wherein at least one selected from a central canal connector and a spacer is provided between the separation membrane element and the separation membrane element adjacent thereto. Membrane module. 1. The sealing member has a through hole or a communication groove, and the through hole or the communication groove is formed closer to the outer diameter than a circle having a diameter intermediate between the outer diameter and the inner diameter of the seal member. The separation membrane module according to any one of 8 to 8. When the seal member has a through hole or a communication groove, and the through hole or the communication groove is observed from the longitudinal direction of the pressure vessel when the seal member is attached to the circumferential groove of the telescope prevention plate. The separation membrane module according to any one of claims 1 to 9, which is formed in a portion outside the diameter of the separation membrane element. The separation membrane module according to claim 9 or 10, wherein the distribution of through holes or communication grooves of the seal member has a sparse portion and a dense portion in the circumferential direction of the seal member. The separation membrane module according to claim 11, wherein the sparse portion of the through hole or the communication groove of the seal member is 50% or less of the entire seal member. The separation membrane module according to claim 11, wherein the sparse portion of the through hole or the communication groove of the seal member is 30% or less of the entire seal member. The separation membrane module according to any one of claims 11 to 13, wherein the seal member is installed so that a portion where the through holes or communication grooves of the seal member are sparsely distributed faces downward in the vertical direction. The separation membrane module according to any one of claims 1 to 14, wherein the sealing member is composed of a C-type split ring seal. Claims 1 to 15 that the closing rate of the gap between the pressure vessel and the separation membrane element when the sealing member is observed from the longitudinal direction of the pressure vessel is less than 30% in at least one sealing member. The separation membrane module according to any one of the above. A plurality of separation membrane elements having a central canal, a separation membrane surrounded by the central canal, and telescope prevention plates provided at both ends of the central canal in the longitudinal direction.
Cylindrical pressure vessel and
With at least one sealing member,
The sealing member closes a part of the gap between the pressure vessel and the separation membrane element.
When the sealing member is observed from the longitudinal direction of the pressure vessel, the closing rate of the gap is 60% or less in at least one sealing member.
A separation membrane module in which a plurality of the separation membrane elements are inserted into the pressure vessel and connected in series by matching the longitudinal direction of the pressure vessel with the longitudinal direction of the separation membrane element. 17. The sealing member has a through hole or a communication groove, and the through hole or the communication groove is formed closer to the outer diameter than a circle having a diameter intermediate between the outer diameter and the inner diameter of the seal member. The separation membrane module described. When the seal member has a through hole or a communication groove, and the through hole or the communication groove is observed from the longitudinal direction of the pressure vessel when the seal member is attached to the circumferential groove of the telescope prevention plate. The separation membrane module according to claim 17 or 18, which is formed in a portion outside the diameter of the separation membrane element. The separation membrane module according to claim 18 or 19, wherein the distribution of through holes or communication grooves of the seal member has a sparse portion and a dense portion in the circumferential direction of the seal member. The separation membrane module according to claim 20, wherein the sparse portion of the through hole or the communication groove of the seal member is 50% or less of the entire seal member. The separation membrane module according to claim 20, wherein the sparse portion of the through hole or the communication groove of the seal member is 30% or less of the entire seal member. The separation membrane module according to any one of claims 20 to 22, wherein the seal member is installed so that the through holes or communication grooves of the seal member are sparsely distributed so as to face downward in the vertical direction. The separation membrane module according to any one of claims 17 to 23, wherein the seal member is composed of a C-type split ring seal. Claims 17 to 24, wherein the closing rate of the gap between the pressure vessel and the separation membrane element when the sealing member is observed from the longitudinal direction of the pressure vessel is less than 30% in at least one sealing member. The separation membrane module according to any one of the above. A method for operating a separation membrane module, which separates a supply fluid into a permeation fluid and a concentrated fluid by using the separation membrane module according to any one of claims 1 to 25.

Images