USE OF A FILTRATION MEMBRANE MODULE

Description

TECHNICAL FIELD

[0001] The present invention relates to a use of a filtration membrane module to perform internal pressure crossflow filtration processing.BACKGROUND ART

[0002] A ceramic filter is a microfiltration device which uses a membrane made of ceramic as a filter, and a filtration membrane such as MF membrane (Micro filtration), UF membrane (Ultra filtration), NF membrane (Nano filtration) and the like having pore size of several µm is used for the filtration processing by selecting the type or mesh size depending on the physical properties and purpose of the material to be processed (Patent Documents 1 to 6).

[0003] As for the purpose of the filtration processing, there are separation, condensation, purification, solvent substitution, pH adjustment, conductivity adjustment, fine particle washing, fine particle surface treatment, classification and the like of the material to be processed, and by filtering waste liquid, it also helps to reduce waste product and protect the environment.

[0004] In general, the filtration processing is roughly classified into two kinds of a total amount filtration system and a crossflow filtration system, and ceramic filter is usually operated in the crossflow system.

[0005] The crossflow filtration system is a system wherein the filtration membrane surface can be always washed away by creating a flow almost parallel to the membrane surface, and filtration is carried out while curbing clogging due to accumulation of the adhering substances such as suspended substances and colloids in the fluid to the filtration membrane surface.

[0006] As mentioned above, because the crossflow filtration system is a system of carrying out the filtration while curbing clogging, in general, it has been known that accumulation of adhering substances on the membrane surface is curbed as the flow velocity of the membrane surface (of the flow of the processing fluid, the flow velocity in the region along the membrane surface of the filtration membrane) is higher. That is, it has been known that the flow amount or the flow velocity of the processing fluid on the filtration membrane markedly affect the filtration characteristics and wash away of the adhering substances.

[0007] However, as the membrane surface flow velocity is increased higher and higher, it is necessary to enhance the strength of pressure-resistance of the circulation route, and to increase facility cost to provide high-power pump equipment or the like as a matter of course, and further the energy consumption and running costs required for the operation are increased. Therefore, the present situation is that the filtration processing has been carried out by designing an economical membrane surface flow velocity in the relation to the required processing amount and washing effect.

[0008] More specifically, the ceramic filter has a substantially cylindrical shape as a whole, and provides a form in which several tubular flowpaths penetrate through inside the cylinder, and the filtration is carried out by circulating a pressurized processing fluid from one end side to the other end side of the tubular flowpath. An inner diameter of the tubular flowpath is about several mm to several cm or so, and usually the filtration is carried out by calculating the flow velocity of the processing fluid relative to this inner diameter.

[0009] However, as mentioned above, the flow velocity of the fluid which flows the tubular flowpath is rapid at the center side and slower at the outer side where the filtration surface exists (membrane surface flow velocity). Accordingly, even when an average flow velocity of the fluid in the tubular flowpath is simply increased, the membrane surface flow velocity cannot efficiently be heightened, thus it does not lead effective use of the energy.

[0010] Also, in the case of a slurry containing fine particles, since the fine particles form aggregate, it is difficult to wash the cleaning object contained in the aggregate.

[0011] Next, although the crossflow filtration system is a system of carrying out the filtration while curbing clogging, when used for certain extent, clogging occurs due to accumulation of adhering substances to fine pores or the like. Thus, by carrying out backwash in which a fluid for washing is passed from the outside of the ceramic filter to the inside of the tubular flowpath, clogging is eliminated. The fluid for washing to be used for backwash is an organic solvent, various kinds of washing liquids, pure water or the like, but in this case, too, a long time and a large amount of the fluid for washing is required, so that it has also been desired to reduce the amount of the fluid for washing and to increase in washing efficiency.

[0012] A rotary filtering plate type filtering machine which employs a crossflow filtration system and is able to efficiently remove a solid component continuously over a long time has been proposed as shown in Patent Document 7. This filtering machine described in Patent Document 7 is comprised of a pair of a disk-shaped chamber plates fixed to a rotary shaft, and a scraper in which is disposed in a filtration room and fixed to a housing so as to scrape a cake layer that accumulates on the filtration surface of the pair of the filtration plates, but it was difficult to apply such a dynamic removing means to a filtration membrane module provided with a hollow cylindrical filtration membrane in which a filtration processing is carried out by feeding the processing fluid with pressure to the primary side by crossflow.

[0013] In Patent Documents 8 and 9, there is disclosure of an invention relating to a filtration membrane module wherein, in a filtration membrane module provided with a hollow cylindrical filtration surface in which a processing fluid is fed by pressure to a primary side and a filtration is carried out by crossflow, wherein a flow adjuster arranged in the primary side flowpath is provided, the flow adjuster is configured to change the flow of the processing fluid passing through the primary side flowpath without being driven by itself, and to give a circumferential component of the primary side flowpath to the flow of the processing fluid passing through the primary side flowpath.

[0014] However, in Patent Document 8, for example, a spirally twisted plate called a rotating element is installed in a module, an effect of generating turbulence is described, but this is not to give a centrifugal separation effect to the processing fluid. In addition, in Patent Document 9, there is disclosure that a spiral-shaped member called a "turbulent flow inducer" is held by a support pipe and turbulent flow is compulsorily and automatically imparted to influent. However, there is no description that the "turbulent flow inducer" held by the support pipe gives a centrifugal separation effect to the influent.

[0015] Patent Document 10 relates to an ultrafiltration separator to remove permeate.

[0016] Patent Document 11 relates to a membrane module.

[0017] Patent Document 12 relates to a device for altering a feed stock.PRIOR ART DOCUMENTSPATENT DOCUMENTS

[0018] Patent Document 1: Japanese Patent Laid-Open Publication No H11-057355 Patent Document 2: International Patent Laid-Open Publication No. WO 99 / 056851 Patent Document 3: Japanese Patent Laid-Open Publication No 2006-263517 Patent Document 4: Japanese Patent Laid-Open Publication No 2006-263640 Patent Document 5: International Patent Laid-Open Publication No. WO 13 / 147272A Patent Document 6: Japanese Patent Laid-Open Publication No 2014-184362 Patent Document 7: Japanese Patent Laid-Open Publication No 2011-016037 Patent Document 8: Japanese Utility Model Publication No. S52-133238 Patent Document 9: Japanese Utility Model Publication No. S52-49353A Patent Document 10: United States Patent No. 5294339 A Patent Document 11: Japanese Patent Publication No. S62-273008A Patent Document 12: United States Patent No. 6077436 A SUMMARY OF THE INVENTIONPROBLEMS TO BE SOLVED BY THE INVENTION

[0019] An object of the present invention is to provide a use of a filtration membrane module wherein in the case where the processing condition of the filtration processing (various conditions of the filtration processing such as diameters of flowpath of the primary side flowpath in the filtration membrane module and in an outer ring-shaped flowpath between a membrane element and an inner peripheral surface of a housing, its flowpath length, flow velocity, fluid pressure, density and viscosity, etc., of the fluid) is set to the same, as compared with the conventional filtration apparatus and filtration method, a centrifugal separation effect and a membrane surface flow velocity (among flows of the processing fluid, flow velocity in a region along a membrane surface of a filtration membrane)are not only enhanced, but also filtration efficiency can be enhanced while curbing accumulation of adhering substances on the membrane surface.

[0020] In addition, an object of the present invention is to provide a use of a filtration membrane module wherein, energy consumption necessary for the filtration can be reduced.

[0021] An object of the present invention is to provide a use of a filtration membrane module wherein, in the case where the processing condition is set to the same, as compared with the conventional filtration apparatus and filtration method, a centrifugal separation effect in the outer peripheral surface of the membrane element and a membrane surface flow velocity (among the flow of the processing fluid, flow velocity in a region along the outer peripheral surface of the membrane element)are not only enhanced, but also efficiency of the backwash processing can be enhanced.

[0022] Also, an object of the present invention is to provide a use of a filtration membrane module wherein, energy consumption necessary for a backwash processing can be reduced.MEANS TO SOLVE THE PROBLEMS

[0023] The present invention is directed to a use of a filtration membrane module according to claim 1.

[0024] The present invention is applied to an internal pressure type filtration membrane module which performs an internal pressure crossflow filtration processing. It is executed as provided with a flow adjuster for backwash arranged in the outer ring-shaped flowpath. The flow adjuster for backwash changes the flow of the fluid for washing passing through the outer ring-shaped flowpath without being driven itself, and by changing the flow of the fluid for washing passing through the outer ring-shaped flowpath with the flow adjuster for backwash, as compared with a flow velocity in the region along the outer peripheral surface in the case where the flow adjuster for backwash is not arranged, a wall surface fluid accelerating function that increases the fluid velocity in the region along the outer peripheral surface of the membrane element in the outer ring-shaped flowpath among the fluids for washing is configured to exhibit.

[0025] The flow-adjuster for backwash is spiral-shaped fins laid in the outer ring-shaped flowpath. The spiral-shaped fins of the flow adjuster for backwash may be a pipe or a round bar formed in a coiled shape or may be a belt-like flat plate formed in a screw (auger) shape.

[0026] In addition, the present invention is to provide a filtration processing method wherein, using the above-mentioned filtration membrane module, crossflow filtration processing is performed on the processing fluid for the purpose of at least one or more of concentration, purification, solvent substitution, pH adjustment, conductivity adjustment, fine particle washing, fine particle surface treatment and classification of the processing fluid.EFFECTS OF THE INVENTION

[0027] The present invention can provide a use of a filtration membrane module wherein as compared with the conventional filtration apparatuses and filtration methods, the membrane surface flow velocity can be enhanced, and filtration efficiency can be improved while curbing accumulation of adhering substances on the membrane surface.

[0028] Also, the present invention can provide a use of a filtration membrane module which can reduce energy consumption necessary for the filtration processing.

[0029] The present invention could be provided a use of a filtration membrane module, wherein as compared with the conventional filtration apparatuses and filtration methods, the membrane surface flow velocity at the filtration surface of the membrane element can be increased and efficiency of backwash processing can be improved.

[0030] Also, the present invention can provide a use of a filtration membrane module which could reduce energy consumption necessary for backwash processing.BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG. 1 is a circuit diagram of the filtration apparatus to which the filtration membrane modules according to the first to the third embodiments of the present invention are applied. FIG. 2(A) is a principal part of sectional explanatory view of the filtration membrane module to which the first to third embodiments of the present invention are applied. (B) is a principal part of sectional view which shows the relationship of the component of the filtration membrane module in the case of internal pressure crossflow filtration, and (C) is a principal part of sectional view which shows the relationship of the component of the filtration membrane module in the case of external pressure crossflow filtration. FIG. 3(A) is a principal part of sectional explanatory view of the filtration membrane module according to the second embodiment of the present invention, and (B) is a principal part of sectional explanatory view of the filtration membrane module according to other embodiments of the present invention. FIG. 4 is a principal part of sectional explanatory view of the filtration membrane module according to the first embodiment of the present invention. FIG. 5 is a principal part of sectional explanatory view of the filtration membrane module according to the third embodiment of the present invention. EMBODIMENTS TO CARRY OUT THE INVENTION(Internal pressure crossflow filtration processing)

[0032] Hereinafter, embodiments of the present invention will be explained with reference to the drawings.

[0033] The crossflow filtration processing is roughly classified into an internal pressure crossflow filtration processing and an external pressure crossflow filtration processing. The internal pressure crossflow filtration processing is a processing method in which a pressurized processing fluid is passed through a membrane element provided with a tubular flowpath inside thereof as a primary side flowpath, and then the filtration liquid generated by the filtration processing is passed through an outside secondary side flowpath. On the other hand, the external pressure crossflow filtration processing is a processing method of using the tubular flowpath inside the membrane element as a secondary side flowpath, and outside the membrane element is made the primary side flowpath, the processing fluid is passed through the outside primary side flowpath and then the filtration liquid generated by the filtration processing is passed through the inside secondary side flowpath of the membrane element. The membrane element is provided with a filtration membrane constituting a filtration surface and a support body 19 which supports the filtration membrane, and the filtration membrane is usually provided on the surface at which the membrane element and the primary side flowpath are in contact. The support body 19 to be used is the one which does not inhibit the processing by the filtration membrane. More specifically mentioned, in the case of the internal pressure crossflow filtration processing, as shown in FIG. 2(B), the filtration membrane is provided along inner wall surface of the tubular flowpath inside the membrane element.

[0034] The present invention can be applied to both filtration processings, three embodiments (the first to the third embodiments) with regard to the filtration apparatus suitable for the internal pressure crossflow filtration processing are shown by referring to FIG. 1 to FIG. 5.(Outline of filtration apparatus)

[0035] First, mainly referring to FIG. 1, an outline of the filtration apparatus suitable for the internal pressure crossflow filtration processing will be explained. The circuit diagram shown in FIG. 1 shows an illustrative example of basic configuration of apparatus that performs filtration processing on various kinds of the processing fluids such as a fine particle dispersion solution and the like, and the filtration apparatus can be executed with applying various kinds of changes such as using plurality of the filtration membrane modules 11 and using stirring apparatus. This filtration apparatus comprises the filtration membrane module 11 which has a housing 12 and a membrane element 13, and a processing liquid tank 55 connected to a primary side introduction port 51 of the filtration membrane module 11 via a liquid feeding pump 56, and the processing fluid inside the processing liquid tank 55 is fed by pressure into the filtration membrane module 11 by the liquid feeding pump 56. The processing fluid fed by pressure passes through the primary side flowpath 14 (see FIG. 2(A)) in the membrane element 13 and is returned to the processing liquid tank 55 from a primary side discharge port 52 via a return valve 61. To the processing liquid tank 55, processing fluid or the like is supplied from a liquid supply source 57 as necessary. The liquid supplied from the liquid supply source 57 may be washing liquid or dilution liquid in addition to the processing fluid and may be supplied to the processing liquid tank 55 from plurality of supply sources through different paths. The presence or absence of supply of the liquid from the liquid supply source 57 and the type and amount of the liquid may be changed depending on the purpose of the filtration and performed.

[0036] By passing the processing fluid fed by pressure through the primary side flowpath 14 in the membrane element 13, crossflow filtration processing is performed. This filtration processing may be performed in one pass and also may be performed repeatedly by a circulation path connecting the filtration membrane module 11 and the processing liquid tank 55. The filtration liquid generated by the filtration processing is discharged to outside the membrane element 13, and then, is discharged to a filtration liquid discharge destination 59 from a secondary side discharge port 54 provided on the housing 12 via a filtration liquid valve 62.

[0037] The processing fluid which has been subjected to the filtration processing is discharged to a processed material discharge destination 58 from a path provided at appropriate part in the circulation path.

[0038] The above mentioned is the circuit and the flow of the fluid to be used at the time of the usual filtration processing, when washing the membrane element 13, a fluid for washing (organic solvent, washing liquid, pure water and the like) from a washing liquid supply source 60 is fed by pressure to a secondary side introduction port 53 provided at the housing 12 via a washing liquid valve 63. The fluid for washing introduced into the housing 12 is introduced from the outer peripheral surface of the membrane element 13 into the primary side flowpath 14 inside thereof and discharged from the primary side introduction port 51 and the primary side discharge port 52 to the processing liquid tank 55 and the like. In addition, not shown in the drawing, the washing liquid may be circulated.(Outline of filtration membrane module 11)

[0039] Next, mainly referring to FIG. 2, outline of the filtration membrane module 11 will be explained. The filtration membrane module 11 comprises membrane element 13 and cylindrical housing 12 disposed outside the membrane element 13. The membrane element 13 comprises at least one (four in FIG. 2) primary side flowpath 14 which is tubular flowpath defined by a hollow cylindrical filtration surface 15. Both ends of the membrane element 13 are connected to the above-mentioned primary side introduction port 51 and the primary side discharge port 52, respectively and are connected to an external circuit via the primary side introduction port 51 and the primary side discharge port 52, pressurized processing fluid is introduced into the primary side flowpath 14 from the primary side introduction port 51, whereby the processing fluid after the crossflow filtration processing is discharged from the primary side discharge port 52.

[0040] As for the filtration membrane constituting the filtration surface 15, ceramic-based materials such as aluminum oxide, zirconium oxide and titanium oxide are mainly used, but it may be a membrane made of stainless or glass, or an organic membrane such as polyethylene, tetrafluoroethylene, polypropylene, cellulose acetate, polyacrylonitrile, polyimide, polysulfone, polyethersulfone and the like. These are used for the filtration processing by selecting the type and size according to the physical properties of the material to be processed or the purpose of the filtration processing such as MF membrane (Micro filtration), UF membrane (Ultra filtration), NF membrane (Nano filtration) and the like. Incidentally, since the ceramic filter is made of ceramic, it is particularly advantageous because there are many merits such as corrosion resistance, heat resistance, pressure resistance, back pressure resistance, durability, cleanability.

[0041] The support body 19 which supports the filtration membrane of the filtration surface 15 is generally a porous ceramic material but may be a tube made of a stainless steel or a porous resin.

[0042] The housing 12 is a hollow cylindrical body and configured by a material having liquid tightness and pressure resistance such as metal, synthetic resin or the like. A space between inner wall of the housing 12 and outer wall of the membrane element 13 configures a secondary side flowpath 16 which is outer ring-shaped flowpath. Whereas the drawing is omitted, both ends of the housing 12 and the membrane element 13 are supported by supporting members, and one filtration membrane module 11 is configured by including other constituent members such as the secondary side introduction port 53 and the secondary side discharge port 54 arranged in the housing 12.

[0043] Incidentally, FIG. 2(B) illustrates the relationship amongst the filtration membrane module 11, the housing 12, the membrane element 13, the primary side flowpath 14, the filtration surface (filtration membrane) 15, the secondary side flowpath 16 and the support body 19 in the internal pressure crossflow filtration processing.

[0044] In the present invention, the flow adjuster 17 shown in FIG. 3 or FIG. 4 is arranged inside the primary side flowpath 14. Also, the flow adjuster for backwash 18 shown in FIG. 5 is arranged inside the secondary side flowpath 16 which is the outer ring-shaped flowpath. The flow adjuster 17 and the flow adjuster for backwash 18 may be used in combination, or only one of them may be arranged to perform.(First embodiment: see FIG. 4)

[0045] The flow adjuster 17 according to this embodiment is executed as a static mixer 21. The static mixer 21 is that a plurality of elements 22 in a form of rectangular blade being twisted with 180 degrees is arranged in the axial direction of the primary side flowpath 14, in the elements 22, a right element and a left element having different twisted directions are generally arranged alternately, however, When applying as the flow adjuster 17, stirring / mixing and dispersing action due to dividing action or a reversing action of the fluid are also effective, a conversion action of the fluid by the elements 22 is important. That is, when the flow direction of the processing fluid changes along streamlined shape surface of the twisted surface of the elements 22, a flow which rotated in the axial direction is generated in the processing fluid. By this, the fluid flowing in the center part of the tubular primary side flowpath 14 of the processing fluids moves to the inner peripheral surface, and the fluid flowing in the inner peripheral surface moves to the center part so as to be pushed by the moved fluid. As a result, the fluid becomes a rotating flow in flowpath having a semicircular cross-section partitioned by the elements 22, whereby a fluid acceleration function which can increase the flow velocity at the region along the filtration surface 15 in the primary side flowpath 14 is exhibited, as compared with the case where no static mixer 21 is provided. Accordingly, the elements 22 may be arranged the right element and the left element having different twisted direction alternately but may be arranged either one of the right element or the left element continuously.

[0046] As an illustrative example of which the above-mentioned stirring / mixing and dispersing action due to the dividing action or the reversing action of the fluid are effective, a case in which the processing fluid is a slurry containing fine particles may be mentioned. In the case of the slurry, since the fine particles form aggregates, it is difficult to remove the target material contained in the aggregates by filtration, but by effectively exhibiting the above-mentioned stirring / mixing, and dispersing action, an action of removing the target material contained in the aggregates is promoted.

[0047] This static mixer 21 may be arranged over the entire length of the primary side flowpath 14, or may be arranged in a part, or may be arranged intermittently.

[0048] The structure in which the static mixer 21 is arranged in the primary side flowpath 14 may be exemplified by a structure in which both ends or one end of the static mixer 21 is / are fixed to the supporting members at the both ends of the filtration membrane module 11, or a structure in which both ends or one end of the static mixer 21 is / are supported directly or indirectly to both ends or one end of the membrane element 13. Incidentally, the outer periphery of the elements 22 may be in contact with or fixed to the filtration surface 15 of the primary side flowpath 14 or may be spaced slightly apart.(Second embodiment: see FIG. 3(A))

[0049] The flow adjuster 17 according to this embodiment is executed as the spiral-shaped fins 31. The spiral-shaped fins 31 are extended in the axial direction of the primary side flowpath 14 while spirally turning, and become a spiral flow which flow along the spiral flow path defined by the spiral fins 31, whereby a fluid acceleration function which can increase the flow velocity at the region along the filtration surface 15 in the primary side flowpath 14 is exhibited. In addition, since an effect of a centrifugal force acts in the spiral flow, a classification effect is also generated in which large fine particles preferentially transfer in the direction of the filtration surface and small fine particles transfer in the direction apart from the filtration surface. As a result, clogging is less likely to occur, so that there is an advantage that the processing ability of the filter itself increases. Incidentally, the direction of twist of the spiral-shaped fins 31 may be a right spiral or a left spiral, or both spirals may be changed in the axial direction of the primary side flowpath 14. By providing a plurality of the spiral-shaped fins 31, a multiple spiral structure of a double or more layers may be used.

[0050] This spiral-shaped fins 31 may be arranged over the entire length of the primary side flowpath 14, or may be arranged in a part, or may be arranged intermittently.

[0051] The structure in which the spiral-shaped fins 31 is arranged in the primary side flowpath 14 may be exemplified by a structure in which both ends or one end of the spiral-shaped fins 31 is / are fixed to the supporting members at the both ends of the filtration membrane module 11, or a structure in which both ends or one end of the spiral-shaped fins 31 is / are supported directly or indirectly to both ends or one end of the membrane element 13. Incidentally, the outer periphery of the spiral-shaped fins 31 may be in contact with or fixed to the filtration surface 15 of the primary side flowpath 14 or may be spaced slightly apart.(Other embodiment of flow adjuster 17: FIG. 3(B))

[0052] The flow adjuster 17 needs only to increase the flow velocity in the region along the filtration surface 15 in the primary side flowpath 14, thus the flow adjuster 17 can be executed in an embodiment other than the static mixer 21 or the spiral-shaped fins 31. For example, by inserting a round bar or a round tube 32 in the primary side flowpath 14, the embodiment which makes a flow of the fluid flowing through the central part of the primary side flowpath 14 move to the region along the filtration surface 15 in the primary side flowpath 14 can be shown. Incidentally, when the round tube is used, it is necessary to close its both ends by an appropriate means.

[0053] However, as long as these round bar or round tubes change the flow direction of the fluid, they become resistant to the flow. Accordingly, as a result of lowering the flow velocity of the whole processing fluid by the resistance, while considering the point that the flow velocity in the region along the filtration surface 15 in the primary side flowpath 14 should not be lowered, it can be executed by setting the diameter and the number thereof.

[0054] Although not shown in the drawing, for example, by providing an inclined plate or a conical body on a support bar extending in the axial direction and the like, the embodiment which makes a flow of the fluid flowing through the central part of the primary side flowpath 14 move to the region along the filtration surface 15 in the primary side flowpath 14 can be shown. However, as long as these static mixer 31, spiral shaped fins 31, inclined plate or conical body change the flow direction of the fluid, they become resistant to the flow. Accordingly, as a result of lowering the flow velocity of the whole processing fluid by the resistance, while considering the point that the flow velocity in the region along the filtration surface 15 in the primary side flowpath 14 should not be lowered, it is appropriate to execute by setting the shape thereof, value of inclined angle or lead angle, or size and number thereof.(Third embodiment: see FIG. 5)

[0055] The third embodiment relates to an embodiment of the flow adjuster for backwash 18. In this example, the flow adjuster for backwash 18 is executed as spiral-shaped fins 41. The spiral-shaped fins 41 are extended in the axial direction of the secondary side flowpath 16 that is the outer ring-shaped flowpath while spirally turning, the fluid for washing for backwash becomes a spiral flow which flow along the spiral flowpath defined by the spiral-shaped fins 41, whereby a wall surface fluid acceleration function which can increase the flow velocity at the region along the outer peripheral surface of the membrane element 13 in the secondary side flowpath 16 is exhibited. In addition, when the washing liquid is circulated and used for the purpose of reducing used amount of the washing liquid, it is also a great advantage that in the spiral flow, foreign materials in the washing liquid are transferred to the housing side by the action of the centrifugal force and a clear washing liquid can be preferentially supplied to the filter side. Incidentally, the direction of twist of the spiral-shaped fins 41 may be a right spiral or a left spiral, or the spirals may be changed in the axial direction of the secondary side flowpath 16. This spiral-shaped fins 41 may be provided over the entire length of the secondary side flowpath 16, may be provided in a part, or may be provided intermittently. By providing a plurality of the spiral-shaped fins 41, a multiple spiral structure of a double or more layers may be used.

[0056] The structure in which the spiral-shaped fins 41 is arranged in the secondary side flowpath 16 may be exemplified by a structure in which both ends or one end of the spiral-shaped fins 41 is / are fixed to the supporting members at the both ends of the filtration membrane module 11, or a structure in which both ends or one end of the spiral-shaped fins 41 is / are supported directly or indirectly to both ends or one end of the housing 12 or the membrane element 13. Incidentally, the outer periphery of the spiral-shaped fins 41 may be in contact with or fixed to the outer peripheral surface or the inner peripheral surface of the secondary side flowpath 16 or may be spaced slightly apart.(Comparison of action of flow adjusters)

[0057] In the internal pressure crossflow filtration processing according to the first to the third embodiments previously shown, the processing fluid is passed through the primary side flowpath 14 which is a tubular flowpath in the membrane element 13. Centrifugal force is acted on the processing fluid by the spiral flow caused by the spiral-shaped fins 31 in the tubular flowpath.

[0058] In the case of splitting off solid solution from the processing fluid, processing is performed in which the particles of the solid component in the processing fluid do not pass through the membrane element 13 and only the liquid component passes through the membrane element 13 and moves to the secondary side flowpath 16.

[0059] At that time, when centrifugal force works, relatively large particles relatively approaches to the filtration surface 15 on the inner wall surface of the tubular flowpath, and relatively small particles are relatively far from the filtration surface 15 on the inner wall surface of the tubular flowpath. Here, the relatively small particles have relatively close in size to the filtration opening of the filtration surface 15, and which cause clogging of the filtration surface 15, thus by relatively apart from the filtration surface 15, occurrence of the clogging of the filtration surface 15 can be curbed.

[0060] On the other hand, in the case of accompanying classification process for separating solid / solid of the processing fluid, for sieving, it is necessary to operate so that only the small particles pass through the filtration surface 15 and no large particles pass through the filtration surface 15. However, in the internal pressure crossflow filtration processing, as mentioned above, when the centrifugal force works on the processing fluid, relatively large particles relatively approach to the filtration surface 15 of the inner wall surface of the tubular flowpath, and relatively small particles relatively far away from the filtration surface 15 of the inner wall surface of the tubular flowpath. Accordingly, when the classification process is accompanied by the internal pressure crossflow filtration processing, there is a risk that the centrifugal force may act in the direction of lowering the efficiency of the classification process.(Filtration processing method)

[0061] The filtration membrane module of the present invention can be applied to a crossflow filtration processing method for various purposes such as concentration, purification, solvent substitution, pH adjustment, conductivity adjustment, fine particle washing, fine particle surface processing and classification of the processing fluid, and the like, similarly to the conventional filtration membrane module with the internal pressure crossflow filtration processing. As described above, depending on the purposes or the type or mode of the processing fluid, it can be executed by selecting MF membrane, UF membrane, NF membrane, and the like, and also, can be executed by changing the circuit of the filtration device. For example, in the processing for the purpose of concentrating the processing fluid, the crossflow filtration processing can be carried out by a circulation path without supplying washing liquid or the like to the processing liquid tank during the processing, and in the processing for the purpose of pH adjustment or conductivity adjustment of the processing fluid, it is also possible to apply the invention according to Japanese Patent No. 6,144,447 and Japanese Patent No. 6,151,469 by the applicant of the present application.EXPLANATION OF THE REFERENCE NUMERALS

[0062] 11 Filtration membrane module 12 Housing 13 Membrane element 14 Primary side flowpath 15 Filtration surface (filtration membrane) 16 Secondary side flowpath 17, 18 Flow adjuster 19 Support body 21 Static mixer 22 Elements 31, 41 Spiral-shaped fins 32 Round bars or round tubes 51 Primary side introduction port 52 Primary side discharge port 53 Secondary side introduction port 54 Secondary side discharge port 55 Processing liquid tank 56 Liquid feeding pump 57 Liquid supply source 58 Processed material discharge destination 59 Filtrated liquid discharge destination 60 Washing liquid supply source 61 Return valve 62 Filtration liquid valve 63 Washing liquid valve

Claims

1. Use of a filtration membrane module (11) to perform internal pressure crossflow filtration processing, the filtration membrane module (11) comprising a membrane element (13) having at least one tubular flowpath (14) defined by a hollow cylindrical filtration surface (15), and a cylindrical housing (12) disposed outside the membrane element (13) defining an outer ring-shaped flowpath (16) between an outer peripheral surface of the membrane element (13) and an inner peripheral surface of the housing (12), wherein, during crossflow filtration, a pressurized processing fluid passes through the tubular flowpath (14) and, during backwashing, a fluid for washing passes through the membrane element (13) from the outer peripheral surface of the membrane element (13) to the tubular flowpath (14), wherein a flow adjuster for backwash (18) arranged in the outer ring-shaped flowpath (16) is provided as spiral-shaped fins (41) laid in the outer ring-shaped flowpath (16), and during backwashing, the flow adjuster for backwash (18) changes the flow of the fluid for washing to a spiral flow passing through the outer ring-shaped flowpath (16) without driving itself so as to increase a flow velocity in a region along the outer peripheral surface of the membrane element (13) in the outer ring-shaped flowpath (16), as compared with a flow velocity in a region along the outer peripheral surface in the case where the flow adjuster for backwash (18) is not provided.

2. Use according to Claim 1 for at least one or more of concentration, purification, solvent substitution, pH adjustment, conductivity adjustment, fine particle washing, fine particle surface treatment and classification of the processing fluid.