JP2018020286A - Pore diffusion membrane separation module for fractionation of component molecules in high molecule solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pore diffusion membrane separation module, in which there is enhanced a fluid fractionation effect capable of fractionating the dissolved component molecules of high molecular weight, and in which the film used is a flat porous one.MEANS FOR SOLVING THE PROBLEM: A pore diffusion membrane separation module is characterized: in that a hydrophilic macromolecule porous film having an average pore diameter of 3 times or more than the high molecule to be fractionated is charged; in that the wall portion of the primary side passage of said porous film contacts the smooth film surface exceeds the length of 50 cm; and in that the take-out port of the recovery liquid to be carried through said film to the secondary side is provided in a plurality at a predetermined length.SELECTED DRAWING: Figure 2

Description

      The module of the present invention relates to a module for fractionating a polymer substance dissolved in a solution by a pore diffusion membrane separation method by making the best use of the flow fractionation effect. In the present invention, pore diffusion membrane separation is (1) in mass transport through a membrane, the permeation rate of substances other than water, which is a medium that permeates pores inside the membrane, is governed by the diffusion mechanism. Membrane permeation of water molecules as the driving force uses transmembrane pressure as the driving force. (3) Transmembrane pressure is less than 0.1 atm. (4) The activation energy of diffusion of the substance that permeates the membrane is 5 kcal / It means separation using a diffusion mechanism having the characteristics of a membrane permeation mechanism of less than mole. Flow separation type pore diffusion membrane separation is a membrane separation that emphasizes the flow separation effect in the above-mentioned pore diffusion membrane separation. (5) The strain rate of the liquid to be treated on the membrane surface is 10 / second or more. (6) It means pore diffusion membrane separation under the condition that the flow of the liquid to be treated on the membrane surface is laminar. Membrane fractionation is a method for separating and purifying substances from multi-component mixed solutions using membrane separation technology to fractionate three or more constituent substances continuously based on specific molecular property values. It is. The membrane separation module has a separation membrane, a space portion filled with the liquid to be treated on the primary side through the membrane, and a space portion for recovering the solution that has passed through the treated membrane, It means a structural unit of a set of apparatuses that perform membrane separation using these parts.

      More specifically, in the membrane separation module of the present invention, a low transmembrane pressure difference of usually 0.1 atm or less is uniformly applied to the entire surface of the membrane, and the liquid to be membrane-treated flows on the membrane surface in a laminar flow. The movement (lift) toward the center of the flow of particles (or molecules), which is a reflection of the flow separation effect generated by this flow, is used. The particle is localized at a distance from the film surface corresponding to its size by a balance between this motion and diffusion based on the Brownian motion of the particle. The presence of this localization means that sorting is performed based on the particle size. That is, separation, concentration, removal, and separation can be performed without clogging of the membrane by flow separation. The transport mechanism of substances inside the membrane is a filtration mechanism for liquid media (liquids such as water and oil), and the transport mechanism of solutes is mainly the diffusion mechanism in the medium that fills the pores in the membrane (intrapore diffusion mechanism). . It is almost impossible to assume a pore diffusion membrane separation technique that emphasizes the flow separation effect in the prior art. Actually, practical examples of membrane separation technology using pore diffusion have been proposed five years ago (Patent Document 1).

      Much of the purification technology for materials using membranes is based on membrane filtration. In membrane filtration, a transmembrane pressure difference of 0.5 to 50 atm is applied, and this is used as a driving force for mass transfer to separate substances mainly by the sieve effect. This method is suitable for solid-liquid separation as a method for separating and purifying a substance that is unstable to heat and chemicals and easily denatured. However, it cannot be a “technique for continuously fractionating and fractionating three or more kinds of component substances”, which is a necessary condition for the technique of membrane fractionation. This is because the pores of the membrane are clogged by membrane filtration, so that it is difficult to separate them continuously, it is difficult to separate them into three or more types, and it is difficult to separate them into three or more types. In addition to membrane filtration methods, methods for separating and purifying physiologically active substances such as proteins and glycoproteins include ultracentrifugation, various types of chromatography, adsorption, dialysis, precipitation / dissolution methods, and the like. The objectives are achieved with these techniques since a small amount of processing is required for analysis purposes. However, when a large amount of treatment is required, it is difficult except for the precipitation / dissolution method. Most of them are batch processing, and it is difficult to incorporate them into a production line as a continuous process.

As a problem that the membrane filtration method has, there is a phenomenon in which pores are clogged as described above. This phenomenon is inevitable as long as the sieving mechanism is used as the separation mechanism. A dialysis method has been conventionally employed as a membrane separation method for preventing clogging. In the dialysis method, dissolution of a substance into a membrane and subsequent diffusion in a substantial part of the membrane (abbreviated as dissolution / diffusion mechanism) are used. However, since the diffusion coefficient is extremely small in the dissolution / diffusion mechanism, there are few examples in which large-scale processing has been put to practical use in a continuous process. The biggest reason for not being put to practical use is that the separation rate is 1/1000 or less of that in the case of filtration. A pore diffusion method has been newly proposed as a membrane separation technique that eliminates this drawback of the dissolution / diffusion mechanism (Patent Document 2 and Non-Patent Document 1).

     The hole diffusion introduced in Patent Document 2 and Non-Patent Document 1 is a steady hole diffusion method, and both the medium (water) and the solute move by the diffusion mechanism, and the problem of clogging is completely eliminated. As a result, the separation speed is 1000 times that of the dissolution / diffusion mechanism, and the slow separation speed is eliminated. However, any solute has a reduced concentration and cannot be concentrated. In steady hole diffusion, the transmembrane pressure difference is practically zero. Therefore, in the steady hole diffusion module, the pump for flowing the liquid on the primary side is a linked pump for making the flow velocity at the inlet and outlet of the module the same. Used. When the membrane to be used is a hollow fiber membrane, the pressure on the inlet side is always higher than the pressure on the outlet side in order to cause the liquid on the primary side to flow inside the hollow fiber. difficult. That is, when the inner diameter of the hollow fiber membrane is 0.5 mm, unless the yarn length is 7 cm or less, the transportation by filtration is dominant due to the pressure for flowing the liquid on the primary side, and the problem of clogging appears. In the case of steady hole diffusion, the secondary side liquid must be supplied in advance through the membrane. There is an advantage that the diffusion rate of the substance can be set because there is a degree of freedom in selecting the liquid on the secondary side, but for the purpose of processing the liquid on the primary side, the presence of this degree of freedom is accompanied by annoying setting of conditions. . In the steady-pore diffusion method, it is possible to continuously separate and fractionate two components (for example, fractionate into a primary side liquid and a secondary side liquid), but when the number of components becomes three or more Continuous separation and sorting is not possible.

    Flow separation type hole diffusion has begun to be studied as a hole diffusion method that eliminates the problems of steady hole diffusion and simplifies liquid processing for the purpose of removing fine particles. (Patent Document 1) A slight transmembrane pressure is applied while flowing a primary side liquid parallel to the membrane surface, and the liquid flowing out to the back side of the membrane through the membrane is caused by the transmembrane pressure difference. This is a technique used as a secondary liquid. A feature of this technique is that the transmembrane pressure difference is indirectly controlled to 0.1 atm by controlling the velocity of the liquid on the primary side and the secondary side. Securing the primary flow path for laminarization as a flow separation type hole diffusion module, and further controlling the flow rate of the liquid on the secondary side and a flat film to withstand the transmembrane pressure difference The support for this must be secured. Further, as shown in the definition of membrane fractionation, it is not possible to continuously fractionate three or more kinds of component substances from a solution in which three or more ingredients are mixed.

Patent Publication 2015-100774 Patent Publication 2006-055780 Rumiko Fujioka, Masako Yoshida, Chizu Yoshimura, Tomoko Yamamura, Seiichi Manabe, Bulletin of Faculty of Human Environment, Fukuoka Women's University, 29, 13-20, 1998.

      Using the state of separation corresponding to the particle size realized in the primary liquid by the flow separation effect (the larger the particle size, the more concentrated it is in the center of the flow) as it is, and the feature of steady pore diffusion It is an object of the present invention to provide a fluid separation type pore diffusion membrane separation module capable of membrane fractionation utilizing mass transport without clogging of certain pores. In order to take full advantage of the flow fractionation effect, the strain rate of the primary liquid flow at the membrane surface must be high. For example, 10 / second or more. When the strain rate is increased, there is a portion where the transmembrane pressure difference increases in the conventional membrane module. For example, the module design can be made to increase the degree of membrane filling and to reduce the amount of liquid remaining in the module. Therefore, in order to increase the strain rate, the flow rate of the liquid must be increased by increasing the difference in static pressure between the inlet and outlet of the primary liquid. Increasing the static pressure at the inlet increases the pressure applied to the membrane surface in the vicinity of the inlet, which contributes to mass transport by membrane filtration and increases clogging of the membrane. It is necessary that the module be capable of giving a predetermined strain rate while maintaining the transmembrane pressure difference uniformly at 0.1 atm or less, desirably 0.05 atm or less throughout the entire film. A module shape that can deny the possibility that the load pressure on the membrane locally exceeds 0.1 atm is required.

      The polymer to be treated must not be modified when the pore diffusion membrane module enables membrane fractionation for a polymer substance. It is necessary to increase the processing speed and to prevent loss of physiological activity such as protein due to local heat generation or distortion during the processing, in particular, the design of the flow path on the primary side. Laminarization of the liquid flow in the primary channel is essential for membrane fractionation. Although it is possible in principle to maximize the processing speed at a constant transmembrane pressure difference, it is necessary to devise a method for minimizing the module volume.

The greatest feature of the module of the present invention is that the majority (30% or more) of the wall surface forming the flow path for the primary liquid (liquid to be treated) is composed of a polymer porous membrane having specific pore characteristics. is there. As specific pore characteristics, the average pore diameter of the membrane is at least 6 times the expansion of the polymer to be fractionated in water (inertia radius rp), the porosity is 60% or more, and the film thickness is 50 μm or more. It is a characteristic. The discovery of the phenomenon in which molecules are fractionated by a membrane having a pore diameter more than 3 times the diameter (2 × rp) of the molecule to be fractionated made it possible for the first time to design the module of the present invention. Considering that separation by conventional membrane filtration shows removability for particles with a particle size approximately equal to the average pore size of the membrane, membrane filtration experience for the purpose of fractionation of particle components is not It is clear that it is almost useless. The precondition that is a module for pore diffusion membrane separation means that the liquid to be processed in the module flows in a laminar flow state, so it is interpreted that the action of the flowing liquid on the particles gives a fractionation function it can. That is, the specified average pore diameter of the porous membrane is determined by taking advantage of the flow separation effect in pore diffusion membrane separation. The relation of the formula (1) was found empirically between the inertia radius of the polymer to be fractionated and the average pore radius rm of the porous membrane.
rm = 2 * (rp) ^1.1 (1) (however, the unit is nm)

      Another feature of the polymer porous membrane employed in the present invention is that the membrane material is a hydrophilic polymer. The target solution to be treated is a polymer solution, and there are cases in which a polymer having physiological activity, such as protein, glycoprotein, sugar chain, or nucleic acid (DNA or RNA) is dissolved in water. Mostly. By making the pore wall surface hydrophilic, loss of physiological activity of the polymer can be prevented. Even if the membrane material is a hydrophobic polymer, hydrophilic treatment only on the membrane surface is defined as a hydrophilic polymer as a membrane material here. The hydrophilic polymer porous membrane is a cellulose non-woven fabric having a dimensional change of 5% or less when dry or wet, or a multistage multilayer structure membrane composed of a porous membrane made of regenerated cellulose and a synthetic polymer non-woven fabric on the back side. The composite film has a dimensional change of 3% or less. Here, when the cross section of the porous membrane portion is observed, a multi-layered multilayered membrane is observed as a stacked layer of layers having a thickness of about 0.2 μm, and the layer surface is parallel to the porous membrane surface. It means a film with a multi-layered structure.

      The second feature of the module of the present invention is that the flow path on the primary side forms a flow path surface that realizes a laminar flow. That is, all the wall surfaces forming the flow path must be smooth. In particular, the unevenness of the surface of the polymer porous membrane constituting the wall surface must be less than the average pore diameter. Due to the flow path on the primary side formed with a smooth surface, the flow on the primary side is laminar with Reynolds numbers below. The length of the primary flow path in the laminar flow state in the module needs to be 50 cm or more, and a large number of the flow paths can be connected in series. However, it is desirable that the cross-sectional area of the circuit of the connecting portion is close to the cross-sectional area of the primary channel.

The cross-sectional shape of the primary flow path is circular or rectangular, the cross-sectional area is 0.1 square cm or more and 10 square cm or less, and the flow path is preferably expressed by a combination of straight lines.
In the case of a cylindrical liquid passage on the primary side, at least one support is present on a part of the wall. That is, there is at least one support that is in close contact with the outer surface of the wall and extends in the flow path direction. The shape of the support is a strip shape or a wire shape, and its longitudinal direction is linear in the flow path direction. The support is in close contact with the outer surface of the wall over the entire flow path of the hole diffusion region. The area of the contact portion occupying the entire area of the wall portion is 1/10 or less. The material of the support is a hydrophobic polymer and is an amorphous polymer having a glass transition temperature of 40 ° C. or higher, or a crystalline polymer having a melting point of 100 ° C. or higher. When the shape of the support is a strip, the thickness is 0.5 mm to 4 mm, and the width is 1 mm to 8 mm. The presence of this support completely prevents the deformation of the flow channel and the deformation of the membrane due to the action of gravity that occurs when the primary flow channel is filled with liquid, and the cross-sectional shape of the flow channel due to the pressure in the flow channel. It is possible to ensure the deforming action of rounding.

      The third feature of the module of the present invention is that a plurality of outlets for the recovered liquid transported to the secondary side through the polymer porous membrane are provided for each predetermined length along the primary channel. It is. That is, the liquid to be treated flows at a rate of, for example, 100 / second through the primary flow path as the strain rate on the membrane surface. Each time a predetermined length passes along the flow on the surface of the membrane, it is individually recovered out of the module through a take-out port determined for each processed liquid recovered through the membrane. However, the module of the present invention is composed of a plurality of serially connected flow separation type pore diffusion membrane separation portions, and the flow of the primary side liquid at the connection portion is substantially equivalent to the flow of the pore diffusion membrane separation portion. When considered as a laminar flow, the integrated connector is also defined as the module of the present invention. In this case, there are a plurality of outlets, and the number of outlets is set corresponding to the number of fractions. As a result of measuring the composition of the recovered liquid through the membrane by flowing the aqueous polymer solution in a laminar flow state along the primary flow path of the present invention and applying a slight transmembrane pressure difference, the take-out port was the primary liquid. The phenomenon that the molecular weight in the recovered liquid is lower as it is closer to the inlet, and the molecular weight of the residual liquid flowing on the primary side increases with time, and the primary side channel design of the module of the present invention and the extraction of the secondary side recovered liquid are found. Mouth design and reached. The distance between the outlets is preferably 20 cm or more and 60 cm or less, and this distance affects the separability of the components in the fractionated solution.

When producing a module of the present invention using a flat membrane, if the cross-sectional shape of the flow path is rectangular, if a pair of parallel wall surfaces forming the flow path is made of a plastic plate, this is Since it also serves as a membrane support, it is easy to mount the porous membrane. When the cross-sectional shape of the flow path on the primary side is a circle, the following difficult points are inherent. That is, (1) A method of deforming into a circular cross section without using a support having a circular cross section with a flat membrane as a wall surface, and (2) Dynamically balancing with gravity generated when a liquid is filled in the flow path. The conventional module cannot add a method of bonding the support and the membrane sharing the tension. We solved this problem in module fabrication as follows. First, the width of the flat membrane is [(the diameter of the primary channel) x (circumference) + the width of the strip-shaped support x2], and the length is cut into the channel length. Two strip-shaped supports are adhered to and adhered to the back surfaces of both end faces of the cut flat membrane. A strip-shaped support is manufactured by winding the flat membrane around the rod of the flow path and keeping the shape of the circular cross-section in close contact with each other using an adhesive.

      It is necessary to realize the membrane fractionation by using the pore diffusion membrane separation module of the present invention under the operating conditions for realizing the pore diffusion. That is, the transmembrane pressure difference is maintained at 0.05 atm or less in all locations of the flat membrane that contribute to mass transport within this module, and the flow rate of the primary fluid is greater than 2 / sec. Preferably it is maintained at 100 / sec. If these two conditions are satisfied, the contribution of membrane filtration can be made almost zero except for the transport of the medium (usually water), so the progress of clogging is ignored when using a pore diffusion membrane module. It becomes possible to do. The transmembrane pressure difference is the most important operating condition for realizing that only molecules (usually water) constituting the liquid medium pass through the pores of the membrane in a volume flow.

      Fractionation of a polymer material using a membrane was made possible by operating the module of the present invention under the operating conditions as a hole diffusion module. That is, at the outlet of the recovery liquid on the secondary side, a polymer substance having a lower molecular weight is fractionated and recovered closer to the inlet side of the fluid on the primary side. Collected as a concentrated solution. Also, clogging of the film during processing is completely prevented. Some high molecular weight components may form aggregates during the fractionation process, in which case they are recovered on the concentration side.

      The benefits of the module of the present invention are particularly significant when the polymer substance is a molecule having physiological activity such as protein. That is, by applying the module of the present invention as a pore diffusion membrane separation module, biological activity is maintained from biological materials containing many kinds of physiologically active substances (for example, body fluids such as blood and lymph, intracellular fluids, extracellular fluids). Many molecules can be fractionated. That is, the module of the present invention can be applied to a fractionation process in a bioprocess. The module of the present invention can minimize the volume and weight per effective area of the flat membrane. Therefore, it is easy to install a device incorporating this module. It can be applied to separation / purification processes such as membrane concentrators, particulate removers, and polymer fractionators incorporating this module. In particular, when the density difference between the substance to be separated / removed / concentrated and the medium is small, fractionation / separation / removal / concentration is possible only by applying the module of the present invention. Specifically, for the emulsion dispersed in the aqueous solution with different particle diameters, the module of the present invention fractionates and collects corresponding to the particle diameter, and the effectiveness of the module of the present invention is remarkable.

      In FIG. 1, two modules for separating pore diffusion membranes of the present invention are connected in series, the solution A to be treated is the primary liquid, and the components in the liquid are classified into three types (residual liquid A, recovered liquids F1 and F2). ) Shows a schematic diagram of an apparatus for fractionation. The average pore size of the cellulosic porous membrane membrane attached to the flow separation type pore diffusion membrane separation module of the present invention indicated by M1 and M2 in the figure is set to about 70 nm when the protein aqueous solution is treated. The pore diffusion separation membrane can be used as a flat membrane with a thickness of 100 μm by producing a regenerated cellulose porous membrane formed by microphase separation on a polyester nonwoven fabric (weight per unit of 15 g / sq.m.) Made of ultrafine yarn. Is done. A large number of tubes (indicated by t in the figure) have the same inner wall cross-sectional area, and are substantially the same as the cross-sectional area of the primary flow path in the module. The edder H is composed of a filter part F through which external air and gas can freely enter and exit, a number of tubes t, and a tube T connected to the pumping pump P. (Hydrostatic pressure) is kept constant. The transmembrane pressure difference in each module is given by the hydrostatic pressure difference (that is, the head difference), and the strain rate at the membrane surface is controlled by the head difference between the inlet and outlet of the primary channel.

  By connecting a number of flow separation type pore diffusion membrane separation modules of the present invention in series, the treatment length by the membrane can be set. The liquid composition after the treatment changes systematically depending on the treatment length. The liquid flowing out through the membrane after the treatment is collected from the outlet from each module. FIG. 1 is a schematic view of a pore diffusion separation apparatus in which two (M1 and M2) are connected in series, and the recovered liquid after treatment in this case is F1 and F2. The composition of the recovered liquid F1 is rich in components having a small molecular weight compared to the composition of F2. It is possible to produce a module in which M1 and M2 are connected. In this module, the number of outlets of the recovered liquid is two. The average pore diameter of the flat membranes used in the two types of modules may be the same or may increase sequentially along the flow path. Transmembrane pressure is given by hydrostatic pressure. The hydrostatic pressure is always constant since it is controlled by the height on the apparatus and the cross-sectional area of the flow path is uniform. The driving force that gives the hydrostatic pressure is the pump P in the figure. The solution that diffuses through the membrane is collected at F1 and F2. The flow rate of the primary liquid is controlled by the head difference between the inlet and outlet of the primary channel. When the average pore diameter is 80 nm, the flat membrane forming the channel has a thickness of 100 μm and a porosity of 75%, and it has been confirmed in advance that the bubble point in water is 0.2 atm or higher. The bubble point as a module must be above 0.1 atm.

Cellulose non-woven fabric (thickness 80 μm) with average pore diameter of 70 nm is used, and the upper and lower parallel walls are parallel to the left and right parallel with the flow path of the primary side liquid in the rectangular cross section with a width of 4 mm and a height of 3 mm. With a simple wall as a membrane support, a polycarbonate strip (thickness 0.5 mm, width 3 mm) is designed to be 100 cm long. As shown in FIG. 2, a device incorporating the module of the present invention in which two pore diffusion membrane modules emphasizing the flow separation effect were integrated by direct connection was produced. However, the module was integrated on the circuit of one type of module instead of two types of connection, and there were two recovery liquid outlets. As a treatment liquid, bovine thymus DNA (manufactured by SIGMA-ALDRICH, molecular weight of about 20 million) dissolved in 10 mM Tris-HCl buffer solution at 0.16 wt% (15 ° C) and ovalbumin 1 wt% were mixed and dissolved. The solution was adopted. The transmembrane pressure difference was 0.01 atm, the strain rate on the membrane surface was 100 / sec, and the treatment rate was LMH = 0.15. The F1 DNA concentration after membrane treatment by this module treatment was 0.01 wt% albumin concentration 0.15 wt%, F2 composition was DNA concentration 0.05 wt%, and albumin concentration 0.12 wt%. When the treatment is continued, the concentration of each component gradually increases. Finally, the composition of F1 is 0.02 wt% for DNA, the albumin concentration is 0.3 wt%, and the composition of F2 is 0.15 wt% for DNA and 0.18 wt% for albumin %. The DNA in the remaining liquid (concentrated liquid) finally reached 1.8 wt% and the albumin concentration reached 0.3 wt%.
A pore diffusion membrane module incorporating flat membranes M1 and M2, which have almost the same pore characteristics, has a flow separation effect due to the flow from the lower side to the upper side of the primary liquid (from right to left in the figure). Different M1 and upper M2 have different effects. Due to this effect, the concentration of the low molecular weight polymer substance in the composition of the recovered liquid F1 is higher than the concentration in the recovered liquid from F2. The treated liquid (concentrated liquid) returns to the concentration tank and is again pumped into the header H by the pump P. The flow rate of the primary liquid is determined by the difference Δh between the header water level and the transition of the module on the primary side flow path to the atmospheric pressure. When the sum of the velocities of the recovered liquids F1 and F2 matches the liquid flow speed Ji before the treatment, the high molecular weight component is continuously concentrated in a steady state.

      It can be used in industries where separation, concentration, removal and sequestration functions using membranes are required, and in industries where components are fractionated. Typically, it is applied to a plasma fractionation process or a body fluid fractionation process. It can also be used for the production of stable feeds for a long period of time by concentration in agriculture, for example, concentration of particulate components in fertilizer (liquid) components. It can be applied to the removal of microorganisms as an alternative to heat sterilization in the fermentation industry, and can be used for the production of new raw products (eg, production of raw placenta). Separation based on size. It can be used in the recycling field (eg, insulating oil recycling, tempura oil recycling) used for fractionation. It can provide basic technology for resource saving in general industrial fields such as removal and separation of harmful substances for effective use of natural resources (eg, production of purified water from snowmelt, arsenic removal from groundwater, etc.).

The schematic diagram of the separation apparatus for fractionation using the built-in module which connected two modules in series. Typical example of a separation apparatus for fractionation incorporating the module of the present invention in which the length of the flow path of the primary liquid is increased to 100 cm or more

A: pore diffusion treatment target liquid, C: concentrate storage tank, f: sterilization filter installed at the outlet communicating with the atmosphere, F1: first fraction of secondary side liquid (liquid component that has passed through the membrane) Recovery port, F2; secondary fraction recovery port for liquid on the secondary side (liquid component that has passed through the membrane), H; header that gives the flow of the primary side liquid and transmembrane pressure difference, Δh; first-stage fractionation The difference between the water level in the header and the water level at the outlet of the primary flow in the module due to the water level difference that becomes the driving force of the flow of the liquid flowing through the module M1 in the process, Ji; Inflow velocity, M1; module used in the first-stage fractionation process, in FIG. 2, the primary liquid flows from the lower part toward the upper part, M2; module used in the second-stage fractionation process, P: A pump for transporting the solution to be treated in the concentration tank to the header H. t: A tube (FIG. 1) that forms the flow of the primary liquid, and the inner diameter thereof is designed to give a cross section approximately equal to the cross sectional area of the primary flow path.

Claims (3)

In the pore diffusion membrane separation module that separates the polymer substance in the components dissolved in the polymer solution based on the size, a module capable of membrane fractionation,
(1) A polymer porous membrane having an average pore diameter of 6 times or more of the polymer to be fractionated in water (inertia radius rp), a porosity of 60% or more, and a film thickness of 50 μm or more is loaded.
(2) The porous membrane constitutes part or all of the flow path on the primary side of the membrane module, the irregularities on the surface of the porous film are less than the average pore diameter, and the length of the flow path in the module is (3) An outlet for the recovered liquid transported to the secondary side through the membrane is set for each membrane of a predetermined length measured along the flow path on the primary side. A pore diffusion membrane separation module for fractionating a polymer, characterized in that a plurality of outlets are independent from each other and a plurality of outlets are present.       2. The flat membrane according to claim 1 is a hydrophilic polymer porous membrane or a nonwoven fabric of hydrophilic polymer fibers, and is composed of a cellulose nonwoven fabric whose dimensional change by drying and wetting is 5% or less, or a material containing 50% or more of regenerated cellulose. And a module having a multistage multilayer structure film, the dimensional change of which is 10% or less. 3. The primary channel according to claim 1 or 2, wherein the cross-sectional shape of the primary channel is circular or rectangular, the cross-sectional area is 0.1 square centimeter or more and less than 10 square centimeters, and the predetermined length of the channel is 20 cm or more and less than 60 cm. A module characterized by being.