JP2008221109A - Liquid separation membrane module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure which is capable of reducing flow resistance of permeate and back washing liquid, is excellent in back washing performance and, moreover, is excellent in productivity in an inner pressure type hollow fiber liquid separation membrane module. <P>SOLUTION: In the inner pressure type hollow fiber liquid separation membrane module, a housing inner diameter is changed in the housing length direction, the housing inner diameter near a permeate outlet is thickened, thereby, a gap between a hollow fiber membrane bundle and the housing near the permeate outlet is enlarged without reducing a packing amount of hollow fiber membranes and a flow path cross-section of the permeate and back washing liquid is enlarged. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an internal structure of an internal pressure type hollow fiber type liquid separation membrane module.

  Separation and purification technology based on membrane separation technology is highly evaluated for its features such as its advanced separation function and energy saving, and it is becoming increasingly popular. Examples of its application fields are production of fresh water by desalination of seawater and brine, surface water and groundwater drinking water, production of pure water and ultrapure water used in the semiconductor industry and pharmaceutical industry, household wastewater and industrial wastewater, Sewerage treatment of municipal sewage and water recovery from wastewater, recovery of valuable materials from fermentation liquor and waste liquid, etc., liquid treatment field, oxygen enrichment and nitrogen enrichment from air, helium recovery from natural gas It covers a wide range of fields, such as gas separation fields such as carbon dioxide separation in the third recovery of oil.

  A fluid separation membrane is a liquid separation membrane such as a reverse osmosis membrane, nanofiltration membrane, ultrafiltration membrane, microfiltration membrane, or oxygen-enriched membrane, nitrogen separation membrane, carbon dioxide gas separation based on the separation target and separation mechanism. It is classified as a gas separation membrane such as a membrane. On the other hand, when focusing on the form of the fluid separation membrane, it is classified into a hollow fiber membrane, a tubular membrane, a flat membrane, a spiral membrane and the like. In the present invention, among the fluid separation membranes, the invention is particularly about the internal pressure type hollow fiber type liquid separation membrane. Hereinafter, in the present invention, unless otherwise specified, the membrane module refers to an internal pressure type hollow fiber type liquid separation membrane assembled in a usable state by connecting a pipe.

  In recent years, there has been a worldwide movement to utilize a membrane filtration method using an ultrafiltration membrane and a microfiltration membrane as a turbidity removal means in water purification treatment. One of the reasons is that it is highly evaluated for its high filtration accuracy compared to the sand filtration method that has been widely used for water purification treatment in the past, and high removability of pathogenic protozoa that have chlorine resistance such as Cryptosporidium. it is conceivable that. In order to further spread the membrane filtration method, it is required to reduce the equipment cost and the operation cost. In order to meet such a demand, various improvements are being made to the membrane module and the membrane filtration system. For example, in order to reduce the operating cost, increase the water permeability per operating pressure, improve the ratio of the production water volume to the supply water volume, that is, the recovery rate, reduce the frequency of chemical washing, extend the membrane life, Etc. are considered effective. Further, it is considered effective to reduce the facility cost by increasing the water permeation amount per membrane module volume, increasing the size of the membrane module, and the like.

  From such a background, conventionally, as an improvement of the membrane module, an increase in the size of the membrane module and an increase in the amount of permeated water per membrane area have been promoted. However, this increases the pressure loss related to the permeate flow in the membrane module and decreases the amount of water per operating pressure, and increases the pressure loss related to the backwash liquid flow in the membrane module to reduce the cleaning efficiency and compensate for it. For this reason, the amount of cleaning liquid is increased and the recovery rate decreases. Problems such as an increase and a decrease in recovery rate, a decrease in film life, or an increase in the frequency of drug washing have become apparent. The following techniques which are considered to be useful for solving these problems are disclosed in the patent literature.

Patent Document 1 discloses a technique of providing a discharge thin film made of a double wall having a wave shape or a hole over substantially the entire length in the longitudinal direction of a capillary filtration membrane. The discharge thin film is connected to a discharge conduit provided in the center of the case in the longitudinal direction of the case, and the permeated water is discharged to the outside of the module through the discharge conduit. On the other hand, the discharged thin film serves as a backwash liquid channel for introducing backwash liquid outside the module during backwashing. According to this configuration, it is possible to prevent damage to the hollow fiber membrane due to a strong flow of permeated water, and it is possible to increase the filling membrane area as compared with the case where a discharge pipe is provided, and to improve the filtration capacity of the module. Are listed. However, since the discharge thin film is connected to the discharge conduit, the number of members is large, the structure is complicated, and the productivity is poor. In addition, it is difficult to uniformly and densely fill the hollow fiber membrane in the gap between the discharge thin films with a cross-sectional fan shape, and the packing density of the membrane cannot be increased, resulting in poor compactness and poor productivity. It is a problem.
JP 2000-246063 A

In Patent Document 2, a cylindrical water collecting body having at least a part of a net-like portion is provided at the center of the case, and a module for backwashing liquid at the time of draining permeated water out of the module and backwashing through this is provided. A technique for introducing the information into the network is disclosed. When this technology is applied to a membrane module having a permeated water outlet on the outer peripheral surface of the case, a communication channel that connects the water collector and the permeated water outlet is necessary. For this reason, the internal structure of the module becomes complicated, resulting in a problem that the productivity is inferior. In addition, since the flow path connecting the water collector and the permeate outlet is formed, it is impossible to fill the portion with a hollow fiber membrane, which reduces the effective membrane area and lacks compactness. End up.
JP 2005-270944 A

Patent Document 3 describes a technique for installing a hollow core membrane bundle in a protective cylinder formed with a constricted portion. According to this invention, the flow outside the hollow fiber membrane is improved and a module can be manufactured at low cost. Has been. However, the operation of filling the hollow cylinder with the constricted protective cylinder is complicated and difficult, and not only the productivity is inferior, but also there is a problem that the hollow fiber membrane may be damaged in the production process. .
Japanese Patent Laid-Open No. 10-337449

  The present invention has been made against the background of such prior art problems. That is, the object of the present invention is, firstly, the pressure loss in the permeate chamber that becomes the flow path of the permeate during permeation is low, and the pressure loss in the permeate chamber that becomes the flow path of the backwash liquid during backwashing is low. It is another object of the present invention to provide an internal pressure type hollow fiber type liquid separation membrane module with high energy efficiency and long life, in which the entire membrane module is uniformly washed. Secondly, it is to provide an internal pressure type hollow fiber type fluid separation membrane module which is simple in structure and excellent in productivity while solving the first problem.

As a result of intensive studies, the present inventors have found that the above two problems can be solved simultaneously by the means described below, and have reached the present invention. That is, this invention consists of the following structures.
(1) A cylindrical case having one or more permeate outlets on the outer peripheral surface,
A hollow fiber membrane bundle is provided in the cylindrical case,
The hollow fiber membrane bundle is sealed between the hollow fiber type separation membranes and between the hollow fiber type separation membranes and the cylindrical case at both ends, and the hollow fiber membrane bundles are sealed in the hollow fiber type separation membranes at both ends of the cylindrical case. The cavity is open,
It comprises a substantially annular space in cross section that is a gap between the hollow fiber membrane bundle and the cylindrical case, and includes a permeate chamber that communicates with the permeate outlet,
The shape of the inner surface of the cylindrical case is any one of a truncated cone, a combination of a plurality of truncated cones sharing a bottom surface, or a combination of at least one truncated cone and at least one cylinder sharing a bottom surface. Internal pressure hollow fiber type liquid separation membrane module characterized by the shape (2) The shape of the inner surface of the cylindrical case shares one truncated cone and the bottom and bottom surfaces of the truncated cone The internal pressure type hollow fiber mold according to (1), characterized in that it is defined by a side shape of a combined body of one circular cylinder and a single circular cylinder sharing the upper and bottom surfaces of the truncated cone. Liquid separation membrane module.
(3) The internal pressure type hollow according to (2), wherein the permeated water outlet is formed so as to be connected to a portion defined by a cylinder that shares a bottom surface and a bottom surface of the truncated cone. Thread type liquid separation membrane module.
(4) The shape of the inner surface of the cylindrical case is two truncated cones, one cylinder sharing the bottom surface sandwiched between the lower bottom surfaces of the two truncated cones, and the upper bottom surface of the truncated cones 2. The internal pressure hollow fiber type liquid separation membrane module according to (1), characterized in that it is defined by a side shape of a combined body of two cylinders sharing each bottom surface.
(5) The permeated water outlet is formed so as to be connected to a portion defined by a cylinder sharing the bottom and bottom surfaces of the two truncated cones. Internal pressure type hollow fiber type liquid separation membrane module.

  According to the present invention, the operating pressure and the backwash pressure can be reduced, energy efficiency can be improved, and the operating cost can be reduced. In addition, since the entire membrane can be washed uniformly during backwashing, it is possible to reduce backwashing time, use backwashing liquid, extend backwashing interval, and extend membrane life, improve energy efficiency during operation, This has the effect of reducing costs. Furthermore, since the internal structure of the membrane module is simple, the manufacturing cost of the membrane module can be kept low.

  Here, the present invention will be described by taking as an example the case of obtaining purified water from surface water or groundwater using an internal pressure type hollow fiber type liquid separation membrane module.

  FIG. 1 is a schematic view showing an entire internal pressure type hollow fiber type water purification membrane module as an example of an embodiment in the case where there is one permeated water outlet 110 in the vicinity of the end with respect to the axial direction of the case. This membrane module includes a cylindrical case 100 and a pair of caps 200 and 300 that close the ends in the axial direction. The case 100 and the caps 200 and 300 are fastened by fastening means 700. Inside the case 100, a hollow fiber membrane bundle 400 made up of a large number of hollow fiber membranes 410 wrapped in a hollow fiber membrane protective cylinder 420 is disposed so as to extend in the axial direction of the case. The case 100 has an internal space formed by a concentric truncated cone and a combination of two circular cylinders that share the bottom and the truncated cone connected to both bottom surfaces. A permeate outlet 110 is provided so as to communicate with the shared cylinder. The inner diameter of the case 100 changes in the length direction of the case, and is thicker in the vicinity of the permeate outlet and thinner as it gets farther from the permeate outlet. Since the diameter of the hollow fiber membrane bundle 400 is constant, the gap between the outer periphery of the hollow fiber membrane bundle 400 and the inner periphery of the case 100 becomes wider as it approaches the permeate outlet. The outer peripheral surface of the hollow fiber membrane protection cylinder 420 has a net shape or a wall shape with a large number of holes through which water can be passed with a water flow resistance that is negligibly small compared to the transmembrane pressure difference. The raw water is filtered by the hollow fiber membrane 410 to purify the water. The upper end portion and the lower end portion of each hollow fiber membrane 410 are sealed and fixed to the case body 100 by a sealing resin 500. That is, the sealing resin 500 is filled in the gaps between the plurality of hollow fiber membranes 410 and the gap between the hollow fiber membranes 410 and the inner wall surface of the case body 100, thereby fixing the hollow fiber membranes 410 in a liquid-tight manner. In the hollow fiber membrane 410, the upper and lower ends thereof are opened, and only the upper end and the lower end are fixed with the sealing resin 500, and the other intermediate portion fulfills the water purification function. The permeate chamber 800 is a space having a substantially annular cross section, which is a gap between the case 100 and the hollow fiber membrane bundle 400, and the upper and lower ends thereof are partitioned by the upper end portion and the lower end sealing resin 500. A permeate outlet 110 is formed near the upper end of the permeate chamber 800. On the other hand, the caps 200 and 300 are made of cap-shaped cap bodies 210 and 310, and openings 220 and 320 are formed, respectively. An air vent 120 (not shown) may be formed near the upper end of the permeate chamber. Further, a drain port 130 (not shown) may be formed near the lower end of the permeate chamber.

FIG. 2 is a schematic diagram showing the entire internal pressure type hollow fiber type water purification membrane module as an example of the prior art when there is one permeate outlet 110 near the end with respect to the axial direction of the case. The case 100 has an inner space formed by a single cylinder, and further includes a permeate outlet 110. Unlike the example of the embodiment of the present invention shown in FIG. 1, the inner diameter of the case 100 does not change in the case length direction and is constant. Therefore, the outer periphery of the hollow fiber membrane bundle 400 and the inner periphery of the case 100 are different. The gap is constant regardless of the distance from the permeate outlet.

  The flow of water when membrane filtration is performed by crossflow and when backwashing is described with reference to FIGS. As shown in FIG. 6, the pressurized raw water is supplied to the inside of the hollow fiber membrane through the opening 220, and a part or all of the raw water passes through the hollow fiber membrane and passes through the permeate outlet 110 to the outside of the membrane module. This flows into the production water, and the remainder flows out of the membrane module through the opening 320 without being filtered. Since raw water contains various contaminants, when the membrane filtration is continued, the contaminants accumulate on the membrane surface and increase the membrane filtration resistance. In order to remove the contaminants and prevent the membrane filtration resistance from increasing, it is common to perform backwashing periodically at intervals of several tens of minutes to several hours. In that case, as shown in FIG. 7, clean water or clean water containing an appropriate cleaning agent such as an oxidizer such as chlorine, an acid, an alkali, a surfactant, or a mixture thereof is supplied from the permeate outlet 110. Pressurized and discharged from one or both openings 220, 320. The backwash flow rate is appropriately adjusted according to conditions such as the degree of increase in membrane filtration resistance, the amount and type of contaminants, backwash time, type of cleaning liquid, etc. Generally, it is about 1.5 to 5 times. A large force is applied to the hollow fiber membrane 410 in the front portion of the permeate outlet 110 due to the direct hit of the cleaning liquid flowing in from the permeate outlet 110 so that the hollow fiber membrane is not damaged. A dispersion plate 600 is installed. FIG. 3 shows a schematic perspective view of the dispersion plate 600. If it is not desirable that the cleaning agent contained in the backwash liquid is mixed into the production water, it is recommended that the cleaning agent be mixed into the production water by rinsing with clean water or discarding the initial filtered water. Can be prevented.

  Considering the flow of permeated water in the membrane module, since the hollow fiber membrane bundle 400 is filled with the hollow fiber membrane 410 at a high density, a flow path is formed outside the hollow fiber membrane bundle. Permeated water mainly flows outside the hollow fiber membrane bundle rather than passing inside the hollow fiber membrane bundle. The permeated water that has flowed out of the hollow fiber membrane bundle flows toward the permeated water outlet 110 that discharges the permeated water from the membrane module, as indicated by thick arrows in FIG. The flow rate of the permeated water is small at a position far from the permeated water outlet 110 and increases cumulatively as the permeated water outlet 110 is approached. Therefore, in the conventional membrane module in which the distance between the outer periphery of the hollow fiber membrane bundle 400 and the inner periphery of the case 100 is equal regardless of the distance from the permeate outlet 110 as shown in FIG. As the distance approached, the amount of water flow per channel cross-sectional area increased, causing a large pressure loss, and wasted energy for flow in the module. On the other hand, it is considered that the flow resistance of the entire membrane module can be reduced by adjusting the size of the channel cross-sectional area according to the size of the flow rate on the left. Here, the flow channel cross-sectional area adjusting means was considered for the flow in the long axis direction of the case, and by changing the shape of the internal space of the case, the vicinity of the permeate outlet became thicker and narrowed away from the permeate outlet, thereby allowing permeation. The inventors have conceived that the flow resistance of water can be reduced and have arrived at the present invention.

  On the other hand, considering the effect of the present invention in the case of backwashing, as shown by the thick arrows in FIG. 7, the backwashing liquid supplied from the permeate outlet 110 partially permeates into the hollow fiber membrane. The remaining part flows toward the back of the membrane module. For this reason, the flow rate of the backwash liquid is large at a portion close to the permeate outlet 110, and the flow rate of the backwash liquid is cumulatively decreased as the distance from the permeate outlet 110 is increased. Since the magnitude of the flow rate corresponds to the magnitude of the cross-sectional area of the flow path, the pressure of the backwash fluid applied to the hollow fiber membrane is leveled, and the entire hollow fiber membrane is effectively washed. In the conventional membrane module, as shown in FIG. 5, the distance between the outer periphery of the hollow fiber membrane bundle 400 and the inner periphery of the case 100 is equal regardless of the distance from the permeate outlet 110. A large pressure loss occurred in the vicinity, and wasteful energy was consumed for the flow in the module.

  In the present invention, regardless of the direction of the truncated cone, the bottom surface having the smaller diameter among the bottom surfaces is referred to as the upper bottom surface, and the bottom surface having the larger diameter is referred to as the lower bottom surface. Further, the truncated cone includes not only a concentric truncated cone but also an eccentric truncated cone, and when simply referred to as a truncated cone, it refers to both the concentric truncated cone and the eccentric truncated cone.

  The case 100 in the present invention has a cylindrical shape, and the shape of the inner surface thereof is a truncated cone, a combination of a plurality of truncated cones sharing a bottom surface, or at least one truncated cone and at least one cylinder sharing a bottom surface. One of the conjugates. It is more preferable that the connecting portion between the cone and the truncated cone be chamfered or connected with a smooth curved surface, since there is an effect of reducing the flow pressure loss of the permeated water and the backwash water.

  In the present invention, the permeate outlet 110 is a portion where the internal space of the case is near the lower bottom surface of the truncated cone in order to widen the flow path width of the permeate chamber near the permeate outlet 110 and reduce the flow pressure loss, or The bottom surface is formed in a portion that is a cylinder sharing the bottom surface of the truncated cone. The position of the permeate outlet 110 in the case length direction may be in the vicinity of the case end as illustrated in FIGS. 1, 8, and 9, and in the vicinity of the center as illustrated in FIGS. 10 and 11. There may be.

  In addition to the permeate outlet 110, an opening for draining may be provided near the lower end of the permeate chamber 800, and an air vent may be provided near the upper end. For example, in FIGS. 1, 8, and 9, an opening is provided so as to connect to the cylindrical portion of the internal space of the permeate chamber 800 that shares the top and bottom surfaces of the truncated cone, and the drain port 130 (in FIG. 1). (Not shown). 10 and 11, an opening is provided so as to connect to the upper cylindrical portion of the cylindrical space sharing the upper and bottom surfaces of the truncated cone in the inner space of the permeate chamber 800, and the air vent port. 120. Further, in FIGS. 10 and 11, an opening is provided so as to be connected to the lower cylindrical portion of the inner space of the permeate chamber 800 sharing the upper and bottom surfaces of the truncated cone, and the drain port. 130.

  In the embodiment shown in FIG. 1 described above, the shape of the inner surface of the case 100 is one concentric truncated cone, one cylinder sharing the lower and bottom surfaces of the left concentric truncated cone, and the left concentric truncated cone. This is an example in which the permeated water outlet 110 is formed so as to be connected to a cylindrical portion that is defined by the upper bottom surface and one cylinder sharing the bottom surface and shares the lower bottom surface and the bottom surface of the concentric truncated cone. On the other hand, the embodiment of FIG. 8 is obtained by replacing the concentric truncated cone with an eccentric truncated cone in the embodiment of FIG. That is, the portion that becomes the permeate chamber 800, which is the internal space of the case 100, includes one eccentric truncated cone, one cylinder that shares the bottom and bottom surfaces of the left eccentric truncated cone, and the upper eccentric truncated cone. A permeated water outlet 110 is formed so as to be connected to a cylindrical portion that is defined by a bottom surface and a single cylinder that shares the bottom surface and shares the bottom and bottom surfaces of the eccentric truncated cone. In this case, the central axis of the hollow fiber membrane bundle coincides with the central axis of the cylindrical portion on the upper bottom surface side, but does not coincide with the central axis of the cylindrical portion on the lower bottom surface side and is eccentric. 9 is obtained by shifting the position of the hollow fiber membrane bundle 400 in the direction away from the permeate outlet 110 in the embodiment of FIG. In this case, the central axis of the hollow fiber membrane bundle is not coincident with both the central axis of the cylindrical portion on the upper bottom surface side and the central axis of the cylindrical portion on the lower bottom surface side, and is eccentric. 8 and 9, as in the embodiment of FIG. 1, the cross-sectional area of the channel is large at the portion near the permeate outlet 110, and the cross-sectional area of the channel is small at the distant portion. The flow resistance of permeated water is low during permeation, the flow resistance of backwash water is low during backwashing, and the pressure of the backwashing fluid is leveled across the entire hollow fiber membrane, so that the entire hollow fiber membrane is washed uniformly.

In the embodiment of FIG. 10, the shape of the inner surface of the case 100 has two concentric truncated cones, one cylinder sharing the bottom surface sandwiched between the lower bottom surfaces of the two concentric truncated cones, and the left concentric cone. It is an example in the case where it is prescribed | regulated by the upper bottom face of a stand, and two cylinders which share each bottom face. The permeated water outlet 110 is formed so as to be connected to a cylindrical portion that shares the bottom and bottom surfaces of the two concentric truncated cones. Further, the embodiment of FIG. 11 is obtained by replacing the two concentric truncated cones with two eccentric truncated cones in the embodiment of FIG. That is, the portion that becomes the permeate chamber 800, which is the internal space of the case 100, has two eccentric truncated cones, and a single cylinder that shares the bottom surface sandwiched between the lower bottom surfaces of the two eccentric truncated cones, It is an example in the case of being prescribed | regulated by the two bottom cylinders which share each bottom face and the upper bottom face of the left-handed eccentric truncated cone. The permeated water outlet 110 is formed so as to be connected to a cylindrical portion that shares the bottom and bottom surfaces of the two eccentric truncated cones.
Also in the embodiment of FIGS. 10 and 11, as in the case of the embodiment of FIG. 1, the cross-sectional area of the channel is large at the portion near the permeate outlet and the cross-sectional area of the channel is small at the portion far from the permeated water outlet. Sometimes the flow resistance of the permeated water is low, the flow resistance of the backwash water is low at the time of backwashing, and the pressure of the backwash fluid is leveled throughout the hollow fiber membrane, so that the entire hollow fiber membrane is washed uniformly.

  In the present invention, the permeate chamber 800 may be partially or entirely filled with a water-permeable filler as long as the flow resistance of the permeate and the backwash water is not greatly increased. Preferred examples of the left-hand filler include a laminate of mesh sheets and a three-dimensional mesh body having a high porosity and a large pore diameter. For example, a three-dimensional network having a structure in which a mesh sheet having a thickness of about 0.5 to 10 mm is laminated, or a large number of bent filaments having a wire diameter of about 0.5 to 10 mm are bonded to each other at the contact portion. Is mentioned. In addition, it is preferable to use a high-stiffness filler for the left-hand filler because it has an effect of suppressing deformation of the hollow fiber membrane bundle when the membrane module is operated at a large flow rate.

  The cross-sectional outer shape of the outer periphery of the hollow fiber membrane bundle 400 in the present invention is substantially circular. If the outer diameter of the cross section of the outer periphery of the hollow fiber membrane bundle 400 is substantially circular, a useless space does not occur in the case, the filling efficiency of the hollow fiber membrane can be increased, and the membrane module has excellent compactness. Can do. FIG. 12 shows a part of a preferred embodiment of the cross-sectional outer shape of the outer periphery of the hollow fiber membrane bundle 400. The substantially circular shape in the present invention includes a circular shape, an elliptical shape, a regular polygon having 6 or more sides, and rounded corners of the regular polygon. In addition, the substantially circular shape in the present invention may be a shape obtained by combining a semicircle and a semi-elliptical shape whose major axis length is equal to the diameter of the semicircular shape on the left, or a shape obtained by combining two semi-ellipses having the same major axis length. In this case, it is preferable to arrange the short axis side toward the permeate outlet 110 side. Or the shape which cut off the permeate outlet 110 opposing part of these cross-sectional shapes may be sufficient. Furthermore, a hollow fiber membrane bundle having a shape of any one of these cross-sectional shapes is formed in advance, and a flow on the permeate outlet 110 side is inserted by means such as inserting a spacer into the gap between the hollow fiber membrane bundle 400 and the case 100. If end bonding is performed in a state where a part or the whole of the hollow fiber membrane bundle is deformed so as to widen the path, a shape in which the outer shape of the hollow fiber membrane bundle is distorted is fixed. The outer shape of the hollow fiber membrane bundle thus obtained is also included in the substantially circular shape in the present invention. Making the cross-sectional shape of the outer periphery of the hollow fiber membrane bundle 400 circular, elliptical, or a shape obtained by deforming a part thereof makes the production process of the hollow fiber membrane bundle simple and highly reproducible, thereby reducing the production cost. From the viewpoint, it is particularly preferable.

  The hollow fiber membrane bundle 400 may be composed of a plurality of small bundles of hollow fiber type separation membranes. The cross-sectional outer shape of the small bundle may be any shape such as a circle, an ellipse, a polygon, and a fan. Further, a gap (hereinafter referred to as a gap between the small bundles) may be formed between the small bundles. When the gap between the small bundles is formed, the gap between the small bundles also functions as a flow path for the permeated water and the backwash water in cooperation with the gap between the outer periphery of the hollow fiber membrane bundle and the inner surface of the case. There is an effect of reducing flow pressure loss in the yarn membrane bundle. Providing the gaps between the small bundles is effective when the outer diameter of the hollow fiber membrane bundle is large, and particularly effective when the outer diameter of the hollow fiber membrane bundle is 100 mm or more. Between the small bundle gaps may be filled with a water permeable filler, and such an embodiment is suitable for the small bundle due to deformation of the small bundle even when there is a flow of permeated water and backwash water at a high flow rate. It is preferable because the clogging between the bundle gaps does not occur and the flow pressure loss effect is surely exhibited.

  When filling the water-permeable filler between the small bundle gaps, it is not always necessary to fill the entire gap between the small bundles. It may be partially filled, and the filler may not be filled particularly in a portion where the flow rate of the permeated liquid and the backwash liquid is small, such as a part far from the permeate outlet. The left permeable filling body preferably has a maximum length in the case axial direction of 60% or more of the effective length of the hollow fiber membrane and not more than the case length, and communicates with the permeate chamber. Preferred examples of the left-hand filler include a laminate of mesh sheets and a three-dimensional mesh body having a high porosity and a large pore diameter. For example, a three-dimensional network having a structure in which a net-like sheet having a thickness of about 0.5 to 5 mm is laminated or a large number of bent filaments having a wire diameter of about 0.5 to 5 mm are bonded to each other at the contact portion. Is mentioned.

  The case 100 in the present invention is a substantially cylindrical container filled with a fluid separation membrane, and has at least one permeate outlet 110 on the outer peripheral surface thereof. The permeated water outlet 110 on the left functions as a fluid inlet / outlet port. In the use state of the fluid separation membrane, both ends of the case are coupled to the cap, or a bottom part integral with the case is formed. An opening may be formed in the bottom integral with the left cap or case. The material of the case and cap is not particularly limited, but engineering plastics such as vinyl chloride resin and polysulfone resin, various reinforced resins such as glass fiber reinforced resin, and corrosion-resistant metal materials such as stainless steel are suitable. The glass fiber reinforced resin is particularly lightweight as a case material because it is lightweight and excellent in corrosion resistance and has good adhesion to the liquid separation membrane sealing resin. Stainless steel is particularly preferable as a cap material because it is excellent in strength and corrosion resistance and can be easily connected to external piping. The case and cap may be uneven or colored according to functional or design requirements.

  Moreover, it is preferable that the caps 200 and 300 in the present invention include an end plate as a constituent element. There are various types of end plates, such as a dish shape, a regular semi-ellipsoidal shape, an approximate semi-elliptical shape, a hemispherical shape, and a flat mirror shape, and any shape may be used. By providing the end plate as a constituent element, the thickness can be reduced compared with a simple bottomed cylindrical type, and the weight can be reduced and the cost can be reduced.

  The fastening method of case 100 and caps 200 and 300 in the present invention is not limited to a specific method. It may be screwed, or a flange provided on the case and the cap may be fastened by a bolt and nut or a swing bolt and nut. Moreover, it is also possible to connect by various pipe joints, and V band coupling, a victic joint, Straub coupling (trademark), etc. are examples of a suitable fastening method.

  The material of the hollow fiber type separation membrane in the present invention is not particularly limited. Preferable examples of the material of the membrane include organic polymer compounds such as polysulfone, polyethersulfone, polyvinylidene fluoride, polyacrylonitrile, polyamide, cellulose acetate, and copolymers, mixtures and modified products containing these. Also, a ceramic film may be used. Further, the separation mode of the hollow fiber type separation membrane is not particularly limited. Any separation mode such as reverse osmosis membrane, nanofiltration membrane, ultrafiltration membrane, microfiltration membrane, etc. may be used.

  As mentioned above, although the example of embodiment of this invention was added, this invention is not limited to these, A various change is possible unless it deviates from the meaning.

  In addition, the liquid separation membrane module is a water purification membrane module made of an internal pressure type hollow fiber membrane, and the case where it is operated by a cross flow filtration method has been described as an example. It can be applied in the same way and demonstrates its effect. Further, the use is not limited to the water purification treatment, and it can be similarly applied to liquid separation membranes having different uses such as wastewater treatment and pretreatment of seawater desalination reverse osmosis membrane.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the examples.

(Method for producing hollow fiber membrane and method for measuring water permeability)
Polyethersulfone (manufactured by Sumitomo Chemical Co., Ltd., Sumika Excel (registered trademark) 4800G) and polyvinylpyrrolidone (manufactured by Nippon Shokubai Co., Ltd., K-30) were heated and dissolved in a mixed solution of dimethylacetamide and triethylene glycol to obtain a spinning dope. . Discharge the spinning stock solution from the outer slit of the double tube nozzle, and simultaneously discharge the aqueous solution of dimethyl ace, amide and triethylene glycol from the inner tube of the double tube nozzle, and after passing through the air, the aqueous solution of dimethylacetamide and triethylene glycol It was led to a coagulation bath consisting of and solidified. Washing with water and hot water washing were carried out, followed by drying with a hot air drier to obtain a hollow fiber membrane having an inner diameter of 0.8 mm and an outer diameter of 1.4 mm. The transmembrane pressure difference 0 extrapolation value of the water permeation flux at a water temperature of 25 ° C. was 30 m ³ / m ² / d / 100 kPa.

(Measurement method of water permeability of membrane module)
A schematic flow diagram of the apparatus used for measuring the water permeability of the membrane module is shown in FIG. The water temperature was adjusted to 25 ± 1 ° C., and the flow rate and pressure were adjusted by adjusting the flow rate adjusting valves 2101, 2102, 2103, and the total amount filtration operation was performed. At that time, the feed water temperature, the permeate flow rate and the operating pressure were measured. As the supply water, water in which tap water was permeated through a reverse osmosis membrane was used. The transmembrane pressure difference P was set to P = (P1 + P2) / 2−P3 with respect to the pressures P1, P2, P3 of the pressure gauges 2201, 2202, 2203.

(Example 1)
A bundle of hollow fiber membranes having a length of 1.2 m is made using 22560 hollow fiber membranes as described above, and the outer peripheral portion of the bundle is covered with a polyethylene mesh (thickness 2 mm). 290 mm). In FIG. 1, the diameter of the lower bottom surface of the concentric truncated cone defining the permeate chamber 800 is 314 mm, the diameter of the upper bottom surface is 300 mm, and 130 mm from the end of the case which is a cylindrical portion connected to the lower bottom surface of the concentric truncated cone. The hollow fiber membrane bundle covered with the left mesh is hollowed in a substantially cylindrical case 100 made of a glass fiber reinforced resin having a length of 1066 mm and an inner diameter of 300 mm, which has a permeate outlet having an inner diameter of 90 mm centered at the position of The thread membrane bundle was inserted so that the central axis thereof coincided with the central axis of the cylindrical portion connected to the lower bottom surface of the concentric truncated cone. Both ends were bonded with a urethane resin adhesive to seal between the hollow fiber membranes and the gap between the case and the hollow fiber membrane, and then the portion protruding from the case end was cut off to open the hollow fiber membrane. The effective length of the hollow fiber membrane (the length of the portion not buried in the sealing portion) was 890 mm. A stainless steel cap was attached to both ends of the case, and a stainless steel dispersion plate was attached to the permeate outlet to form a membrane module. The transmembrane pressure difference required to obtain a permeate flow rate of 18 m ³ / hr was 32 kPa.
(Example 2)
A membrane module was prepared in the same manner as in Example 1 except that the center axis of the hollow fiber membrane bundle was shifted by 3 mm in the direction opposite to the permeate chamber outlet. The transmembrane pressure difference required to obtain a permeate flow rate of 18 m ³ / hr was 31 kPa.

(Comparative Example 1)
A membrane module was prepared in the same manner as in Example 1 except that the permeate chamber 800 had a cylindrical shape with an inner diameter of 300 mm. The transmembrane pressure difference required to obtain a permeate flow rate of 18 m ³ / hr was 81 kPa.

  According to the fluid separation membrane module of the present invention, the operating pressure can be reduced, and the operating cost can be reduced and the energy efficiency can be improved. In addition, since the cleaning liquid can uniformly clean the entire membrane module during backwashing, there are effects of reducing the frequency of chemical washing and extending the membrane life. These effects are beneficial for users of fluid separation membrane devices.

It is a mimetic diagram of an internal pressure type hollow fiber type water purification membrane module of an example of an embodiment of the present invention. 1A is a schematic diagram of a longitudinal section of the entire membrane module, FIG. 1B is a schematic diagram of a transverse section in the BB section of FIG. 1A, and FIG. 1C is FIG. It is a schematic diagram of the cross section in CC section. It is a schematic diagram of an example of the conventional internal pressure type hollow fiber type water purification membrane module. FIG. 2A is a schematic diagram of a longitudinal section of the whole membrane module, and FIG. 2B is a schematic diagram of a transverse section in the BB section of FIG. 2A. FIG. 2 is a schematic perspective view of a dispersion plate 600 used in FIG. 1. It is a schematic diagram which shows the flow of the water at the time of filtration of an example of the conventional internal pressure type hollow fiber type water purification membrane module. FIG. 4A schematically shows a vertical cross section, and FIG. 4B schematically shows a cross sectional state of the BB cross section of FIG. 4A. It is a schematic diagram which shows the flow of the water at the time of backwashing of an example of the conventional internal pressure type hollow fiber type water purification membrane module. FIG. 5A schematically shows a vertical cross-section, and FIG. 5B schematically shows a cross-sectional state of the BB cross-section of FIG. 5A. It is a schematic diagram which shows the flow of the water at the time of filtration of the internal pressure type | formula hollow fiber type water purification membrane module of an example of the embodiment of this invention. 6A is a vertical cross-section, FIG. 6B is a cross-sectional view taken along the line BB, and FIG. 6C is a schematic cross-sectional view taken along the line CC in FIG. 6A. . It is a schematic diagram which shows the flow of the water at the time of backwashing of the internal pressure type | formula hollow fiber type water purification membrane module of an example of the embodiment of this invention. 7A is a vertical cross-section, FIG. 7B is a cross-sectional view taken along the line BB, and FIG. 7C is a schematic cross-sectional view taken along the line CC in FIG. 7A. . It is a schematic diagram which shows the example of the other embodiment in this invention. FIG. 8A is a schematic diagram of the entire membrane module, FIG. 8B is a schematic diagram in the BB cross section of FIG. 8A, and FIG. 8C is a CC cross section in FIG. It is a schematic diagram. It is a schematic diagram which shows the example of the other embodiment in this invention. 9A is a schematic diagram of a longitudinal section of the whole membrane module, FIG. 9B is a schematic diagram of a transverse section in the BB section of FIG. 9A, and FIG. 9C is FIG. 9A. It is a schematic diagram of the cross section in CC section. It is a schematic diagram which shows the example of the other embodiment in this invention. 10A is a schematic diagram of a longitudinal section of the entire membrane module, FIG. 9B is a schematic diagram of a transverse section in the BB section of FIG. 10A, and FIG. 10C is FIG. 10A. It is a schematic diagram of the cross section in CC section. It is a schematic diagram which shows the example of the other embodiment in this invention. 11A is a schematic diagram of a longitudinal section of the entire membrane module, FIG. 11B is a schematic diagram of a transverse section in the BB section of FIG. 11A, and FIG. 11C is FIG. 11A. It is a schematic diagram of the cross section in CC section. It is a schematic diagram which shows the example of the other embodiment of the cross section equivalent to the BB cross section in Fig.1 (a) in this invention. It is a schematic flowchart of the apparatus which performed the water-permeable performance measurement of the membrane module in the Example and comparative example of this invention.

Explanation of symbols

100: Case 110: Permeated water outlet 120: Air vent 130: Drain port 200: Lower cap 210: Lower cap body 220: Lower cap opening 300: Upper cap 310: Upper cap body 320: Upper cap opening 400: Hollow fiber membrane bundle 410: hollow fiber membrane 420: hollow fiber membrane protective cylinder 500: sealing resin 600: dispersion plate
610: Dispersion plate shielding portion 620: Dispersion plate fixing portion 630: Dispersion plate support portion 700: Fastening means 800: Permeate chamber 1001: Auxiliary line 2001: Supply water tank 2002: Temperature adjusting device 2003: Stirrer 2004: Supply pump 2005 : Membrane modules 2101, 2102, 2103: Flow control valves 2201, 2202, 2203: Pressure gauge 2301: Flowmeter

Claims (5)

A cylindrical case having one or more permeate outlets on the outer peripheral surface,
A hollow fiber membrane bundle is provided in the cylindrical case,
The hollow fiber membrane bundle is sealed between the hollow fiber type separation membranes and between the hollow fiber type separation membranes and the cylindrical case at both ends, and the hollow fiber membrane bundles are sealed in the hollow fiber type separation membranes at both ends of the cylindrical case. The cavity is open,
It comprises a substantially annular space in cross section that is a gap between the hollow fiber membrane bundle and the cylindrical case, and includes a permeate chamber that communicates with the permeate outlet,
The shape of the inner surface of the cylindrical case is any one of a truncated cone, a combination of a plurality of truncated cones sharing a bottom surface, or a combination of at least one truncated cone and at least one cylinder sharing a bottom surface. Internal pressure hollow fiber type liquid separation membrane module characterized by shape   The shape of the inner surface of the cylindrical case is one truncated cone, one column sharing the lower bottom surface and bottom surface of the left truncated cone, and one column sharing the upper bottom surface and bottom surface of the left truncated cone. 2. The internal pressure hollow fiber type liquid separation membrane module according to claim 1, which is defined by a side shape of the combined body.   3. The internal pressure hollow fiber type liquid according to claim 2, wherein the permeate outlet is connected to a portion defined by a cylinder sharing a bottom surface and a bottom surface of the truncated cone. Separation membrane module.   The shape of the inner surface of the cylindrical case is two truncated cones, one cylinder sharing a bottom surface sandwiched between the lower bottom surfaces of the two truncated cones on the left, the upper bottom surface of each of the left truncated cones, and each bottom surface 2. The internal pressure hollow fiber type liquid separation membrane module according to claim 1, wherein the internal pressure hollow fiber type liquid separation membrane module is defined by a side shape of a combined body with two cylinders sharing the same. 5. The internal pressure hollow according to claim 4, wherein the permeate outlet is formed so as to be connected to a portion defined by a cylinder sharing a bottom surface and a bottom surface of the two truncated cones. Thread type liquid separation membrane module.

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