EP2734288A1 - Membrane module for organophile pervaporation - Google Patents

Abstract

The invention relates to a membrane module (1) for pervaporation, in particular organophile pervaporation, having a liquid-tight housing (11) with at least one feed inlet (12, 37), at least one retentate outlet (6a, 13, 13') and at least one permeate outlet (14, 42) that is or can be subjected to a negative pressure or vacuum, wherein a membrane pocket stack (15) is arranged in a housing interior (18) and has a plurality of membrane pockets (20) and seals (65) laid on one another, wherein mechanical pressure is or can be applied to the membrane pockets (20) in the stacking direction by means of a pressure application device (32, 33) for the mutual sealing of the membrane pockets (20), so that the housing interior (18) is divided up by the membrane pockets (20) into a feed chamber (26) on the outside of the membrane pockets (20) and a permeate chamber (27) in the interior (20) of the membrane pockets. The invention further relates to a use of a membrane module (1) according to the invention. The membrane module according to the invention is characterized in that the membrane pockets (20) have a substantially rectangular cross section and, in their membrane surfaces, have openings (22) in the form of slots, wherein the slot-like openings (22) arranged on one another in the membrane pocket stack (15) and the seals (65) located therebetween form at least one common permeate channel (40), which leads to the at least one permeate outlet (14).

Description

 Membrane module for organophilic pervaporation Description

The invention relates to a membrane module for, in particular organophilic, pervaporation, with a liquid-tight housing having at least one feed inlet, at least one Retentatauslass and at least one can be acted upon or acted upon by a vacuum or vacuum Permeatauslass, wherein a membrane pocket stack is arranged in a housing interior, a plurality of has superimposed membrane pockets and seals, wherein the membrane pockets are acted upon or acted upon by a Druckbeaufschlagungsvorrichtung for mutual sealing of the membrane pockets in the stacking direction with mechanical pressure, so that the housing interior through the membrane pockets in a feed space on the outside of the membrane pockets and a Permeatraum inside the membrane pockets is divided. Furthermore, the invention relates to a use of a membrane module according to the invention.

CONFIRMATION COPY Pervaporation is a process for the purification of liquid mixtures and is based on the separation effect of membranes, which are different permeable to different liquid components by diffusion. For each application, a suitable membrane must be chosen, by which the component present in lower concentration, also called the minor component, diffuses better through than the majority component which is present in excess. An example of this is, for example, the separation of bioethanol, which contains, for example, 96% by weight of ethanol and 4% of water, ie an azeotopic mixture which can no longer be separated by other separation processes. For this purpose, for example, a hydrophilic membrane is chosen, in which the minor component water can enter well, while the ethanol is rejected by the membrane stronger.

In contrast to pressure-driven filtration methods, the membrane is impermeable to liquids except for diffusion. The pervaporation is operated by applying a negative pressure or a vacuum on the permeate side, while on the feed side, although a feed flow is generated, but this is not associated with particular pressure.

The pervaporation is driven by the fact that the liquid components of the feed flow diffuse through the membrane and hit on the permeate side of the membrane to a strong negative pressure or a vacuum. Thus, the permeate evaporates instantaneously on the permeate side of the membrane and thus reaches the permeate outlet. This pressure difference between the vacuum or low air pressure on the permeate side and the normal liquid pressure on the feed side, which is also the retentate side, drives the diffusion process or the pervaporation process. This process can also be based on the concentration the solution component which diffuses through the membrane is considered, since the concentration of this liquid component at the feed side of the membrane is large and at the permeate side is low due to the evaporation on the permeate side. This concentration gradient drives the pervaporation process. The rate at which pervaporation occurs therefore depends on the prevailing pressure difference on either side of the membrane for any point on the membrane.

There are various designs of membrane modules for pervaporation in the art. Most membrane modules are based on flat membranes. Thus, in the case of a plate module from Sulzer-Chemtech with an open permeate space, a membrane is clamped between a feed plate and a module end plate, a permeate channel spacer with a perforated plate being arranged on the permeate side. Here is a complicated seal required.

In a plate module from CM-Celfa with closed permeate space alternate membrane plates and impermeable plates, which also requires a high sealing effort.

In an alternative design construction, alternating layers of flat membranes are wound in a spiral winding module about a central porous permeate tube, between which layers of feed spacer and layers of permeate spacer are alternately arranged. The feed stream is fed in parallel to the permeate tube. This design is only of limited suitability for use in pervaporation processes.

Finally, the applicant has a membrane module for pervaporation based on a membrane pocket stack with at their Rims welded round membrane pockets, which are stacked on a central porous permeate tube. The membrane pockets with a round cross-section each have a central, round opening whose radius coincides with the diameter of the permeate tube. The membrane pockets, with their two membrane surfaces lying one on top of the other, are held open by permeation pacers inside the membrane pockets, so that applying a negative pressure in the permeate tube does not cause the membrane pockets to collapse. In addition, the membrane pockets are sealed at their contact lines together with the permeate tube so that the outer sides of the permeate pockets in the membrane module result in a feed space which is sealed by a permeate space on the inside of the membrane pockets and the permeate tube.

In contrast, it is the object of the present invention to provide a membrane module for pervaporation, by means of which a further improved separation efficiency, in particular an increased permeate amount, is achieved at the same time with consistently good selectivity.

This object is achieved by a membrane module for, in particular organophilic, pervaporation, having a liquid-tight housing with at least one feed inlet, at least one retentate outlet and at least one permeate outlet which can be acted upon or acted upon by a vacuum or vacuum, wherein a membrane pocket stack is arranged in a housing interior , which has a plurality of superimposed membrane pockets and seals, wherein the membrane pockets are acted upon or acted upon by means of a pressurizing device for mutual sealing of the membrane pockets in the stacking direction with mechanical pressure, so that the housing interior is divided by the membrane pockets into a feed space on the outside of the membrane pockets and a permeate space in the interior of the membrane pockets, which is further developed in that the membrane pockets have a substantially rectangular cross-section and in their membrane surfaces have slot-like openings, wherein the in Membrane pocket stack stacked on each other slot-shaped openings and seals therebetween form at least one common permeate channel, which leads to the at least one permeate outlet.

The invention is based on the idea that a membrane module developed by the applicant with a Mebrantaschen- stack with substantially circular membrane pockets and circular central opening for a central permeate tube is changed to the effect that the geometry in favor of a larger pressure difference between the permeate side and feed side of the membrane is changed. In the conventional membrane modules with flat membranes, this problem had not come up, since the pressure difference between the permeate side and the feed side at each point of the flat membranes was the same. Applicants' membrane module pocket round mem- brane pockets did not have this problem because the separation efficiencies in both selectivity and permeation rates were comparable or superior to those of conventional prior art modules. However, it has surprisingly been found that the permeation rate through the membranes can be significantly increased again by changing the geometry.

This is due to the fact that permeate, which flows at a location of a circular membrane pocket, which is located radially far outward, as gas in the direction of the center to the permeate tube got to. This applies to permeate, which flows in from any point in the membrane pocket. In the direction of the central permeate tube, the permeate assumes an ever smaller volume, so that it is compressed in the direction of the center. This compression is associated with increased resistance and pressure drop. This means that a strong pressure difference arises from the outer areas of the membrane pockets towards the center, so that in the outer areas the negative pressure, which is applied to the permeate side of the membrane, is less pronounced than in the center. Thus, the driving force for the diffusion of the liquid-lesser component in the membrane in the outer region of the membrane pocket is much less strong than in the inner region where the pressure difference between the permeate side and the feed side of the membrane is greater than in the outer region. This leads to an inefficiency of the pervaporation process in the outer region of the membrane, ie in the larger area of the membrane pockets. The pressure loss curve is particularly pronounced in the interior of the membrane pockets, while flattening off radially outwardly. Therefore, a large part of the membrane area is affected by the inefficiency.

In these considerations, the thickness of the membrane pockets, so the distance between the membranes of the membrane pocket, plays only a minor role, since this is kept constant by means of Permeatspacern in the radial direction. The increasing pressure loss has to do mainly with a change in the size of the membrane pocket in the circumferential direction, which can be illustrated by concentric circular rings of the same thickness, the surface of which shrinks linearly as the radius decreases.

The choice of a substantially rectangular cross-section of the membrane pockets and a slot-shaped opening leads to a change of the flow structures of the permeate in the membrane. rantaschen. Instead of flowing radially from the outside to a center and thus accepting a reduction in cross-section, the permeate now reaches a straight path largely without cross-sectional constriction to the central slot. Only in the immediate end region of the oblong hole or slots there are converging flow lines, which lead to a similar pressure loss. By contrast, the flow lines do not converge or only barely converge over the length of the elongated hole, as a result of which the pressure loss from the inside to the outside in the membrane pockets is significantly reduced. Thus, in a large part of the area of the membrane pockets, similar low values of the negative pressure are present, so that in these areas there is a large pressure difference between the permeate side and the feed side of the membranes, which ensures a very efficient pervaporation. The achievable pervaporation rates, ie permeate levels, can be increased in this way many times without negatively influencing the selectivity of the separation of the minor component and the majority component.

Preferably, the slot-shaped openings are arranged on the longer of the two axes of symmetry of the membrane pockets. With this measure, the areas of the membrane pockets in which non-converging permeate flows are present are maximized and areas in which permeate flow lines converge are minimized. This improves the efficiency of the pervaporative separation.

In an advantageous development, the at least one permeate channel opens into a permeate tube on one side of the membrane pocket stack, which has one or more permeate outlets. In this case, therefore, the vacuum is not applied directly to a permeate channel in the membrane pocket stack, but to a permeate tube on one side or both sides of the permeate tube, which simplifies the construction of the membrane module as a whole. In this way, the slot-shaped cross section of the permeate channel or the permeate channels in the membrane pocket stack is converted into a tubular cross section which is better suited for applying a reduced pressure.

Instead of an oblong-shaped permeate channel, a plurality of slot-shaped permeate channels may be provided in a row adjacent to each other. This is provided in particular in one embodiment of the membrane module in which the pressure application device has tie rods which lead from one side of the membrane pocket stack to the other side of the membrane pocket stack and are arranged in an axis of symmetry of the membrane pockets in order to ensure the most uniform possible pressure build-up, for example by means of a pressure plate , In such a case, the slots of the permeate channels and the tie rod (s) then alternate on the symmetry axis.

Preferably, porous permeate spacers are arranged in the membrane pockets and / or porous feed spacers between membrane pockets in the membrane pocket stack. The porous permeate spacers serve to prevent the membrane pockets from collapsing upon application of negative pressure and thus to define a constant permeate space in the membrane pockets. The permeate spacers are porous and have sufficient strength to preserve the shape of the membrane pockets even when negative pressure is applied. The feed spacers serve to stabilize the membrane pockets, in particular with regard to the feed flow in the membrane module. This ensures a constant geometry of the membrane pocket stack and also ensures that the membranes of the successive membrane pockets do not touch each other that as large a surface as possible is available for pervaporation.

Advantageously, a plurality of permeation spacers are arranged in the membrane pockets in layers, the fineness of the porosity increasing from the inside to the outside. Thus, for example, in the center with respect to the thickness of the membrane pockets, a layer of a coarse Permeatspacers be provided, for example, crosswise superimposed polymer threads, while outwardly decreases the thickness of the polymer threads and optionally in a outermost layer, a fine nonwoven fabric is arranged, which has a certain small-scale flexibility and in particular has relatively little contact surface with the permeate side of the membrane of the membrane pockets, so that the largest possible flow cross section on the permeate side of the membranes for the pervaporation is actually available.

To further stabilize the membrane pocket stack as well as the permeate channels or the permeate channel, one or more pressure plates are additionally arranged between the membrane pockets and a permeate spacer between the membrane pockets. The pressure plates absorb the pressure forces exerted by the seals arranged between the membrane pockets on the diaphragms and form an abutment for the seals. Thus, the seal between the feed space and Permeatraum is still improved.

It is further preferably provided that in the at least one permeate channel, a perforated support tube for stabilizing the permeate or the permeate is arranged, which has substantially the same cross-section as the permeate. Such a support tube prevents seals or parts under the action of the vacuum present in the interior of the membrane stack be sucked inward on membrane pockets, so that would be broken in the interior of the housing as a result of such an event, the seal between the feed space and Permeatraum. In this case, the feed fluid could freely penetrate into the permeate space. A support tube reliably prevents such an incident.

In an advantageous development of the membrane module according to the invention, the housing interior is divided into several subspaces or compartments by means of deflecting disks arranged between individual membrane pockets, wherein the deflecting disks each comprise openings for guiding a feed flow from one compartment to the next compartment, the openings being arranged alternately to create a meandering feed flow through the compartments. The generation of a meandering feed flow ensures that the feed stream is guided in succession over several membrane pockets in the successive compartments, so that the effective membrane area which presents itself to the feed stream is multiplied. This leads to a further increase in the efficiency of the porous separation of the liquid mixture.

This is preferably further developed in that the height of the compartments and the number of membrane pockets per compartment at least partially decrease in the direction from the feed inlet to the retentate outlet. Thus, the cross section, which is available to the feed stream, narrows continuously in the interior of the housing from the feed inlet to the retentate outlet, which results in an increasingly greater flow velocity. This also means that at the beginning, close to the feed inlet, the concentrated feed liquid comparatively long with a comparatively large number of membrane pockets and thus one dwells large membrane surface and thus at the beginning already a relatively strong separation of the minor component takes place from the liquid mixture. In the subsequent compartments, the flow velocity is increased due to the lower compartment height and the number of available membrane pockets in the compartment is reduced, thus also the available membrane area, so that in this area the meanwhile enriched area is avoided Majority component of the liquid mixture vaporized. Also, a different distribution of the numbers of membrane pockets per compartment is included according to the invention, for example, a reduction, which merges into an increase in the number of membrane pockets per compartment to Retentatauslass. The variation can be adjusted as required.

In the membrane module according to the invention, the housing is preferably arranged in a pressure vessel.

Furthermore, the object underlying the invention is also achieved by using a previously described membrane module according to the invention for the pervaporative separation of liquid mixtures, in particular mixtures of organic solvents and organic substances dissolved therein.

The features, advantages and properties mentioned for the membrane module according to the invention also apply without restriction to the use according to the invention of the membrane module.

Further features of the invention will become apparent from the description of embodiments according to the invention together with the claims and the accompanying drawings. Embodiments of the invention may be individual features or a Combine several features.

The invention will be described below without limiting the general inventive idea by means of embodiments with reference to the drawings, reference being expressly made to the drawings with respect to all in the text unspecified details of the invention. Show it:

1 is a schematic view of a disk module of the prior art,

Fig. 2 is a schematic representation of another

 Plate module of the prior art,

3 is a schematic representation of a spiral winding module of the prior art,

Fig. 4 is a schematic cross-sectional view through a known membrane pocket module

5 is a schematic representation of a known round membrane bag,

Fig. 6a), 6b) schematic representation of the flow lines in

 Membrane pockets,

7 is a perspective view of a pressure vessel of a membrane module according to the invention,

8 shows a schematic front view of a membrane module according to the invention, 9 is a Aufrisszeichnüng to a membrane module according to the invention,

10 is a side cross-sectional view through a membrane module according to the invention,

1 1 is a schematic detail of a cross section through a membrane module according to the invention,

Fig. 12 are schematic representations of a seal and

Fig. 1 3 is a schematic representation of a pressure plate.

In the drawings, the same or similar elements and / or parts are provided with the same reference numerals, so that apart from a new idea each.

In Fig. 1, a plate module 100 from Sulzer-Chemtech with open Permeatraum in an exploded view is shown schematically in perspective. Between a top plate 104 and a bottom plate 105, a feed plate 106 with a circumferential seal 107, a membrane 108 and a perforated plate 109 with subsequent Permeatkanalspacer 1 10 are arranged sealingly. For this purpose, the upper plate 104 and the lower plate 105 are firmly connected to one another by means of screws and the layers lying therebetween are subjected to pressure on the circumferential seal 107 and thus sealed against one another.

The upper plate 104 has inputs for a feed 101 on a liquid component enriched with a minor component. mixed as well as for an outlet for a retentate 102 on the opposite side. In addition, it is shown on the underside that permeate exits through the permeate channel 103 through the permeate channel spacer 110 in different directions. Here, the circumferential seal 1 07 must be carried out consuming to ensure a secure seal of the feed space from the permeate.

2, a plate module 200 from CM-Celfa with closed permeate space is shown schematically in an exploded view. The plate module 200 comprises a stack or tower of a top plate 204, alternating membrane plates 205 and intermediate plates 207, and a final end plate 209, which are shown spaced apart to illustrate the principle of operation but sealingly disposed in the plate module 200. The plates 204, 205 and 207 have at their corners in each case openings for feed channels 201, retentate channels 21 1 and permeate channels 212, through which in each case a feed 201, a retentate 202 or a permeate 203 pass.

The membrane plates 205 each have a diamond-shaped membrane 206, which are connected to the openings for the permeate channels 212. With the intermediate plates 207 framing them, each membrane 206 divides the space between two successive intermediate plates 207 into a feed space and a permeate space. In each feed space, a feed liquid flows transversely from the feed channel 201 to the opposite retentate channel 21 1. In the respective Permeatraum the permeate diffuses from the entire membrane surface to the two permeate channels 212. The flow arrows for liquids are each provided with a black arrow end, while the flow arrows for the gaseous streams, so the permeate, with a white arrow end are provided.

In Fig. 3 schematically illustrates a membrane module according to an alternative design principle, namely a spiral winding module 300 having a perforated tube 304 in the center. Two flat membranes 305 are spirally wound around this tube, between which a permeate spacer 306 or a feed spacer 307 is alternately arranged. To this spiral winding module 300, a feed 301 is introduced into the spiral membrane part in the direction of the perforated tube 304, which feed exits again as retentate 302 on the other side. Permeate enters the porous tube 304 from the space between the membranes 305 filled with the permeate spacer 306 and exits the tube 304 as a retentate 302.

FIG. 4 schematically shows a membrane module 400 with a stack of membrane pockets 409 in cross section, which has been developed by the applicant. This has a container 404 or a housing which has a feed inlet 406 for a feed 401, which, guided by deflecting disks 408 which are arranged alternately on different walls of the container 404, is guided in the changing flow direction through the container 404 and on a retentate outlet 407 emerges as retentate 402 again. In the interior of the container 404, a stack of membrane pockets 409 is arranged, which are arranged around a central permeate tube 405 around and sealed by O-rings 410 against the feed 401.

The membrane pockets 409 of the pervaporation module 400 in FIG. 4 have a substantially circular circumference and the central opening with the permeate tube 405 is circular. The feed 401 is meandering passed through the container 404, that he respectively flows along the outer surfaces of the membrane pockets 409 along. The minor component diffuses more than the majority component of the feed 401 through the membranes of the membrane pockets 409 and reaches the inside of the membrane where it vaporizes and flows to the permeate tube 405 and is aspirated as gaseous permeate 403 at the ends of the permeate tube 405.

FIG. 5 schematically shows a plan view of a membrane pocket 409 of the pervaporation module 400 according to FIG. 4. The membrane pocket 409 is shown partially circular in FIG. 5, although two parallel straight side lines are also present. The central opening with the permeate tube is circular. By means of the solid illustrated arrows, it is shown that a feed stream 420 flows from one side to the membrane pocket 409, flows over it and continues to flow as retentate stream 421.

The dot-dashed arrows indicate the direction of flow of the evaporated retentate in the interior of the membrane pocket 409, ie the permeate stream 422. It can clearly be seen that the permeate stream 422 is directed toward the center from all directions.

FIGS. 6 a) and 6 b) schematically show the flow conditions in a membrane pocket 20 according to the invention with a rectangular cross-section and slot opening 22 and a conventional round membrane pocket 409, as also shown in FIG. 5. While the circular membrane pocket 409 shown in Fig. 6b) has a permeate flow 422 with converging flow lines toward the central permeate tube 405, the flow lines of the permeate flow 25 in Fig. 6a) are parallel to each other. They also remain almost parallel to each other up to the side surfaces of the membrane pocket 20. Only directly at the side surface do some convergent, not shown, currents arise. tion lines. Of these, only a small, peripheral part of the membrane pocket 20 is affected.

In contrast, the flow lines of the retentate flow 422 of the circular membrane pocket 409 in Fig. 6b) are convergent everywhere. This reduced flow cross-section leads, in contrast to the parallel flow lines in Fig. 6a), to an increase of the flow resistance and thus to an increased pressure loss from the inside to the outside in the membrane pocket 409 and thus to a decreasing driving force of the diffusion of the minor component of the liquid mixture in the feed through the membrane. In the case of the rectangular membrane pocket 20 according to FIG. 6 a) with the parallel flow lines, the flow cross-section does not sink, so that a significantly lower flow resistance is present. As a result, the pressure loss to the outside in the rectangular membrane bag 20 is much lower, so that even in the outer regions of the rectangular membrane bag 20, a high pressure difference between the permeate side and feed side of the membrane is present, the diffusion of the minor component of the feed through the membrane drives. This is created by the combination of the rectangular geometry of the membrane pockets and the arrangement of the geometry of the elongated holes in the membrane pockets 20.

FIG. 7 shows a schematic view of a membrane module 1 according to the invention for pervaporation, which is particularly suitable for pervaporation of organic liquid mixtures, for example for the separation of benzene from relatively high molecular weight washing liquids or for the purification of bioethanol.

The membrane module 1 has a cylindrical pressure vessel 2, which through a front plate 3 and through a cover plate 4th is sealed, which are screwed to annular end flanges of the pressure vessel 2. In the front panel 3, a feed connection piece 5 is arranged centrally at the bottom and two retention pins 6, 6 'arranged at the top, between which a permeat connection piece 7 is additionally arranged centrally. In the perspective view of FIG. 7, a similar Permeatanschlussstutzen in the end plate 4 is not shown, because it is hidden in perspective.

In FIG. 8, the membrane module 1 according to FIG. 7 without front panel 3 shown from the front. In the cylindrical pressure vessel 2, an inner container 1 1 is arranged with a feed inlet 12 at the bottom and retentateauslasses 13, 1 3 'and a permeate outlet 14 at the top. The flow direction of the feed is thus from bottom to top, from the feed inlet 12 to the Permeatausläs- sen 14. In the inner container 1 1 a membrane pocket stack 15 is arranged with a plurality of membrane pockets 20, wherein the interior 18 of the inner container 1 1 by deflecting 16 is additionally divided into several compartments 17a-17f, the height decreases in the flow direction of the feed from bottom to top. The last two compartments 1 7e and 17f, however, are the same size.

In Fig. 9, a part of the membrane module 1 is shown in partial elevation. The cylindrical pressure vessel 2 is sealed by the front plate 3, which is bolted to a flange of the cylindrical pressure vessel 2. In the elevation of the inner container 1 1 is shown, wherein the membrane pocket stack 1 5, the deflection discs 16 and some compartments are shown. The interior opens into a retentate 6a, which opens into a Retentatanschlussstut- zen 6 '. Above the membrane pocket stack 15 is a permeate tube with a permeate connection piece 7. As shown in FIG. 9, the deflecting disks 16 have openings 16a for feeding the feed from one compartment to the next. It can also be seen how the membrane pockets 20 divide a feed space 26 outside the membrane pockets 20 of a permeate space 27 within the membrane pockets 20.

In Fig. 10, the complete inner container 1 1 of the membrane module 1 according to the invention is shown schematically in a cross-sectional view. The inner container 1 1 has end plates 30 and side plates or side walls, not shown, and a top plate 31 and a lower pressure plate 32, which are connected to each other by means of a plurality of tie rods 33. For this purpose, each tie rod 33 is secured at its upper side by means of nuts 34 and at the opposite end to clamping nuts 36 which press with O-rings 35 against the pressure plate 32. By tightening the nuts 34, the pressure exerted by the tie rods 33 on the pressure plate 32 can be amplified. In this case, by setting a uniform bias of the tie rod 33, a uniform pressure on the membrane pocket stack 15 are exercised. Another O-ring 35 'seals the top plate 31 from the outside in the pressure vessel 2.

In the pressure plate 32, a feed channel 37 is shown on the left side through which the feed liquid enters the first compartment 1 7a and from left to right in FIG. 10 flows past the membrane pockets 20 outside. The circulating edge seal 21 of the membrane pockets 20 can also be seen. After flowing through the first compartment 1 7a from left to right, the feed stream reaches the opening 16a in the first deflection disk 16 and enters through this into the second compartment 1 7b it flows through from right to left in Fig. 10. There it encounters the next opening in the next deflection disk 16, through which it enters the next compartment 1 7c. In this way, a meandering flow of the feed through the membrane module 1 is adjusted by the deflection disks 16 and the alternating arrangement of the openings 16a in the deflection disks 16, so that the feed flows several times past membrane pockets 20 and has the opportunity several times that dissolved in the feed Release minor component to the permeate.

Between the tie rods 33 are in the membrane pocket stack 1 5 slot-shaped Permeatkanäle 40, which are formed by the succession of the slots 22 in the membrane pockets 20. These are in the embodiment of FIG. 10 each supported by a porous support tube 43 which is shown in phantom. The support tubes 43 prevent the permeate channels 40 from collapsing under the negative pressure applied to the permeate outlets 42. These permeate channels 40 and porous support tubes 43 open into a permeate tube 41, which opens into permeate outlets 42 on both sides.

By a circle in the right part of Fig. 10 and the letter "X" is a detail of the membrane bag stack 1 5 identified, which is shown in Fig. 1 1 in detail and from which the detailed structure of the membrane bag stack 15 emerges.

Each membrane pocket 20 accordingly has a circumferential, for example welded, edge seal 21, on which the membranes which form the membrane pocket 20 are firmly connected to one another. To run inward, the membranes of the membrane pocket first diverging and then parallel and form the actual membrane pocket 20. Since the membrane pocket 20 under Application of negative pressure would be located inside the membrane pocket 20 Permeatspacer 52 to 55. In the center of a large Permeatspacer 55 is arranged, which is surrounded on both sides by a finer Permeatspacer 54. These are in turn surrounded on their outside by very fine Permeatspacern 53. These can also be surrounded by a fleece 52. The permeate spacers 53, 54 and 55 may, for example, consist of layers of plastic threads arranged one above the other in a crosswise arrangement, the degree of fineness of which increases towards the outside, while the nonwoven fabric has an irregular structure.

In addition, 1 1 pressure plates 60 are arranged on the inner sides of the membrane of the membrane pockets 20 in Fig. 1, which give the membrane pockets 20 additional stability. These are used in particular to give slot seals 65, which are arranged between the consecutive membrane pockets 20, an opponent, in order to reliably separate the permeate space 27 in the interior of the membrane pockets 20 and in the permeate channels 40 from the feed space 26 outside the membrane pockets 20. Both the pressure plates 60 and the slot seals 65 are located in or around the membrane pockets 20 only in the immediate vicinity of the slot-shaped permeate channels 40.

In Fig. 12a), 12b), a slot seal 65 is shown schematically. In Fig. 12a), the plan view in the direction of the permeate channels 40 is shown. In this view, the elongated hole seal 65 has a circumferential bead of sealing material 67, for example an elastic material, for example rubber. A flat frame 66 has openings 68 for tie rods 33 and openings 69 for permeate channels 40. Such a slot seal 65 is inserted between successive membrane pockets 20 at the location of the permeate channels 40 and the tie rods 33. In Fig. 12b) is a cross-sectional view through the slot seal 65 along the section line AA of Fig. 12a) is shown in a larger magnification. In the middle of this cross-sectional view, the slot seal 65 has the opening 69 for a permeate channel 40. This is bounded on the top and bottom of a frame 66 having the corresponding opening 69 at this point. The frame 66 includes on its sides the sealing material 67, which occurs bead-shaped on the sides 66 on the sides.

FIG. 13 shows a corresponding pressure plate 60 in the same perspective view as the slot seal 65 from FIG. 12a). In the pressure plate 60 shown in FIG. 13 is a flat body made of an incompressible or less compressible material, such as a metal or plastic, in its circumference and in the arrangement of openings 31 for tie rods 33 and openings 62 for Permeatkanäle 40 of the arrangement of the openings 68 and 69 of the slot seal 65 of FIG. 12a) corresponds. The pressure plate 60 is arranged in the membrane pockets 20 and serves as a counterpart for the slot seals 65 in order to absorb the pressure forces when tightening the tie rods 33.

All mentioned features, including the drawings alone to be taken as well as individual features that are disclosed in combination with other features are considered alone and in combination as essential to the invention. Embodiments of the invention may be accomplished by individual features or a combination of several features. LIST OF REFERENCE NUMBERS

1 membrane module

 2 cylindrical pressure vessel

 3 front panel

 4 end plate

 5 feed connection piece

 6, 6 'Retentant connection piece

 6a retentate channel

 7 permeate connection pieces

 1 1 inner container

 1 2 Feed inlet

 1 3, 13 'retentate outlet

 14 permeate outlet

 1 5 Membrane bag stack

 16 deflection pulley

 16a opening

 17a - 1 7f compartment

 18 interior

 20 membrane bag

 21 edge seal

 22 slot-shaped opening for a permeatkana

23 Feed flow

 24 retentate flow

 25 permeate flow

 26 feed room

 27 permeate space

 30 face plate

 31 top plate

 32 pressure plate

 33 tie rods

34 mother O-ring

locknut

Feed channel

permeate

permeate

permeate

porous support tube for the permeate channel Feedspacer

fleece

very fine permeate spacer

fine permeate spacer

coarse permeate spacer

Andruckblech

Opening for tie rods

Opening for permeate channel

Slot seal

frame

sealing material

Opening for tie rods

Opening for permeate channel

board module

Feed

retentate

permeate

upper plate

lower plate

Feed plate

poetry

membrane

perforated sheet

Permeatkanalspacer

board module 201 feed

 202 retentate

 203 permeate

 204 cover plate

 205 membrane plate

206 membrane

 207 intermediate plate

208 profile

 209 end plate

 21 0 feed channel

21 1 Retentate channel

212 permeate channel

300 spiral winding module

301 feed

 302 retentate

 303 permeate

 304 perforated tube

305 membrane

 306 permeate spacer

307 feedspacers

400 membrane module

401 Feed

 402 retentate

 403 permeate

 404 containers

 405 permeate tube

406 feed intake

407 retentate outlet

408 deflection pulley

409 membrane bag

410 O-ring

420 feed stream Retentate flow Permeate stream

Claims

Membrane module for organophilic pervaporation claims 1. membrane module (1) for, in particular organophilic, pervaporation, with a liquid-tight housing (1 1) with at least one feed inlet (12, 37), at least one Retentatauslass (6a, 13, 13 ') and at least one with a vacuum or vacuum can be acted upon or acted upon Permeataus- let (14, 42), wherein in a housing interior (18) a membrane pocket stack (15) is arranged, which has a plurality of superimposed membrane pockets (20) and seals (65), wherein the membrane pockets (20) by means of a pressurization device (32, 33) for mutual sealing of the membrane pockets (20) in the stacking direction acted upon or acted upon by mechanical pressure, so that the housing interior (18) through the membrane pockets (20) in a feed space (26) on the outside of the membrane pockets (20) and a permeate space (27) in the interior of the membrane pockets (20) is divided, characterized net, that the membrane pockets (20) have a substantially rectangular cross-section and in their membrane surfaces slot-shaped openings (22), wherein in the membrane pocket stack (15) successive arranged slot-like openings (22) and intervening seals (65) at least one common permeate (40) leading to the at least one permeate outlet (14). Membrane module (1) according to claim 1, characterized in that the slot-shaped openings (22) are arranged on the longer of the two axes of symmetry of the membrane pockets (20). Membrane module according to claim 1 or 2, characterized in that the at least one permeate channel (40) opens into a permeate tube (41) on one side of the membrane pocket stack (1 5) having one or more permeate outlets (14, 42). Membrane module (1) according to one of Claims 1 to 3, characterized in that porous permeate spacers (52-55) are arranged in the membrane pockets (20) and / or porous feed spacers (51) between membrane pockets (20) in the membrane pocket stack (15). Membrane module (1) according to claim 4, characterized in that a plurality of permeate spacers (52-55) are arranged in layers in the membrane pockets (20), the fineness of the porosity increasing from the inside to the outside. Membrane module (1) according to claim 4 or 5, characterized in that in the membrane pockets (20) additionally an or a plurality of pressure plates (60) are disposed between the membrane and a permeate spacer (52-55). Membrane module (1) according to one of claims 1 to 6, characterized in that in the at least one permeate channel (40) a perforated support tube (43) for stabilizing the permeate (s) (40) is arranged, which has substantially the same cross section as the Permeate channel (43). Membrane module (1) according to one of claims 1 to 7, characterized in that the housing interior (18) by means of individual membrane pockets (20) arranged deflecting discs (16) into a plurality of compartments (17a - 1 7f) is divided, wherein the deflection discs (16 ) each comprise openings (16a) for guiding a feed flow (23) from one compartment (17a-17e) to the next compartment (17b-117f), the openings being arranged alternately, through a modifying feed flow (23) to create the compartments (17a - 17f). Membrane module (1) according to claim 8, characterized in that the height of the compartments (1 7a - 17f) and the number of membrane pockets (20) per compartment (1 7a - 1 7f) in the direction from the feed inlet (12) to the retentate outlet (23 , 13 ') at least partially decrease. Membrane module (1) according to one of claims 1 to 9, characterized in that the housing (1 1) in a pressure vessel (2) is arranged. Use of a membrane module (1) according to one of claims 1 to 10 for the pervaporative separation of liquid keitsgemischen, in particular mixtures of organic solvents and dissolved organic substances.