Plate-and-Frame Fluid Separation Module and Assembly, and Process for Using the Same

Abstract

Plate-and-frame membrane modules, assemblies and processes for separating components of a fluid mixture. The assemblies comprise of a pressure vessel filled with, and able to hold, pressurized fluid being processed. Lightweight membrane plate-and-frame modules are contained inside the vessel. Fluid directing conduits direct the fluid streams being processed into and out of the vessel and across the surface of the separating membrane. Because the modules are surrounded by high pressure fluid, the forces acting on the module are small. This means the modules can be made of lightweight, inexpensive materials, such as plastic. The design of the assemblies is such that it allows for modules to be easily replaced as needed. The assemblies are also designed for pressurized feed fluid separations and separation using a sweep fluid on the permeate side of the membrane. The pressure vessel can contain one or several membrane modules.

Claims

1. A fluid separation assembly, comprising: (a) a plate-and-frame fluid separation membrane module, the module comprising: i. a housing comprising a first end plate and a second end plate, ii. at least one pair of membranes positioned between the first and second end plates, wherein one side of each membrane bounds a permeate channel running the length of the module, said permeate channel having at least one end that is open, and located adjacent to the other side of each membrane is a feed channel running the length of the module, each feed channel being in fluid-transferring communication with a feed inlet at one end of the channel and a residue outlet at the other end of the channel; (b) a vessel containing the fluid separation membrane module, the vessel comprising: i. a shell, ii. an annular space within the shell, said annular space being in fluid-transferring, communication with the feed inlets of the module, iii. a feed conduit in fluid transferring communication with the annular space, iv. a permeate conduit connected to and in fluid-transferring communication with the open end of the permeate channel, and v. a residue conduit connected to and in fluid-transferring communication with the residue outlets of the module.

2. The fluid separation assembly of claim 1, further comprising a plurality of separation membrane modules.

3. The fluid separation assembly of claim 2, wherein the assembly further comprises a plurality of permeate conduits, one for each module, and a plurality of residue conduits, one for each module.

4. The fluid separation assembly of claim 1, wherein the other end of the permeate channel is closed.

5. The fluid separation assembly of claim 1, wherein the other end of the permeate channel is open and the vessel further comprises a sweep conduit in fluid-transferring communication with said other end of the permeate channel.

6. The fluid separation assembly of claim 1, wherein the other end of the permeate channel is open and the vessel further comprises a second permeate port in fluid-transferring communication with said other end of the permeate channel.

7. The fluid separation assembly of claim 1, wherein the housing of the module is made of plastic.

8. The fluid separation assembly of claim 1, wherein the fluid separation membrane module is configured to be removable from the vessel by detachment of the permeate channel from the permeate conduit and the residue outlet from the residue conduit.

9. The fluid separation assembly of claim 1, wherein the vessel farther comprises at least one removable head.

10. The fluid separation assembly of claim 1, wherein the plate-and-frame fluid separation membrane module contains a plurality of pairs of membranes, wherein for each pair of membranes, one side of each membrane bounds a permeate channel running the length of the module, said permeate channel having at least one end that is open, and located adjacent to the other side of each membrane is a feed channel running the length of the module, each feed channel being in fluid-transferring communication with a feed inlet at one end of the channel and a residue outlet at the other end of the channel.

11. The fluid separation assembly of claim 10, wherein the plate-and-frame fluid separation module contains between 20 and 50 pairs of membranes.

12. The fluid separation assembly of claim 10, further comprising a permeate manifold connected to and in fluid-transferring communication with both the open end of each permeate channel of each pair of membranes and the permeate conduit.

13. The fluid separation assembly of claim 1, wherein the membranes are selectively permeable to carbon dioxide over nitrogen and carbon dioxide over oxygen.

14. A fluid separation process using the assembly of claim 1, comprising: (a) introducing a feed fluid mixture into the feed conduit and allowing the teed fluid mixture to flow from the annular space and into the feed inlets and along the feed channels, wherein the annular space and the feed channels are at substantially similar pressures; (b) providing a driving force to induce permeation of a first portion of the feed fluid mixture from the feed channel side of the membranes to the permeate channel side of the membranes; (c) withdrawing from the permeate conduit a permeate stream comprising the first portion; and (d) withdrawing from the residue conduit as n residue stream a second portion of the feed fluid mixture.

15. A fluid separation process using the assembly of claim 6, comprising: (a) introducing a feed fluid mixture into the feed conduit and allowing the feed fluid mixture to flow from the annular space and into the feed inlets and along the feed channels, wherein the annular space and the feed channels are at substantially similar pressures; (b) providing a driving force to induce permeation of a first portion of the feed fluid mixture from the feed channel side of the membranes to the permeate channel side of the membranes; (c) passing a sweep stream across the permeate channel side of the membrane; (d) withdrawing from the permeate conduit a permeate stream comprising the first portion; and (e) withdrawing from the residue conduit as a residue stream a second portion of the feed fluid mixture.

16. The process of claim 14 or 15, wherein the feed fluid mixture is a gas mixture comprising carbon dioxide from the combustion of carbon-containing fuels.

17. A fluid separation assembly, comprising; (a) a plate-and-frame fluid separation membrane module, the module comprising: i. a housing comprising a first end plate and a second end plate, ii. at least one pair of membranes positioned between the first and second end plates, wherein one side of each membrane bounds a permeate channel running the length of the module, said permeate channel having at least one end that is open, and located adjacent to the other side of each membrane is a feed channel running the length of the module, each feed channel being in fluid-transferring communication with a feed inlet at one end of the channel and a residue outlet at the other end of the channel; (b) a vessel containing the fluid separation membrane module, the vessel comprising: i. a shell, ii. an annular space within the shell, said annular space being in fluid-transferring communication with the residue outlets of the module, iii. a feed conduit connected to and in fluid-transferring communication with the annular space, iv. a permeate conduit connected to and in fluid-transferring communication with the open end of the permeate channel, and v. a residue conduit in fluid-transferring communication with the annular space.

18. The fluid separation assembly of claim 17, further comprising a plurality of separation membrane modules.

19. The fluid separation assembly of claim 18, wherein the assembly further comprises a plurality of permeate conduits, one for each module, and a plurality of residue conduits, one for each module.

20. The fluid separation assembly of claim 17, wherein the other end of the permeate channel is closed.

21. The fluid separation assembly of claim 17, wherein the other end of the permeate channel is open and the vessel further comprises a sweep conduit in fluid-transferring communication with said other end of the permeate channel.

22. The fluid separation assembly of claim 17, wherein the other end of the permeate channel is open and the vessel further comprises a second permeate port in fluid-transferring communication with said other end of the permeate channel.

23. The fluid separation assembly of claim 17, wherein the housing of the module is made of plastic.

24. The fluid separation assembly of claim 17, wherein the fluid separation membrane module is configured to be removable from the vessel by detachment of the permeate channel from the permeate conduit and the residue outlet from the residue conduit.

25. The fluid separation assembly of claim 17, wherein the vessel further comprises at least one removable head.

26. The fluid separation assembly of claim 15, wherein the plate-and-frame fluid separation membrane module contains a plurality of pairs of membranes, wherein for each pair of membranes, one side of each membrane bounds a permeate channel running the length of the module, said permeate channel having at least one end that is open, and located adjacent to the other side of each membrane is a feed channel running the length of the module, each feed channel being in fluid-transferring communication with a feed inlet at one end of the channel and a residue outlet at the other end of the channel.

27. The fluid separation assembly of claim 26, wherein the plate-and-frame fluid separation module contains between 20 and 50 pairs of membranes.

28. The fluid separation assembly of claim 26, further comprising a permeate manifold connected to and in fluid-transferring communication with both the open end of each permeate channel of each pair of membranes and the permeate conduit.

29. The fluid separation assembly of claim 17, wherein the membranes are selectively permeable to carbon dioxide over nitrogen and carbon dioxide over oxygen

30. A fluid separation process using the assembly of claim 17, comprising: (a) introducing a feed fluid mixture into the feed conduit and passing the feed fluid mixture to the feed inlets and along the feed channels; (b) providing a driving force to induce permeation of a first portion of the feed fluid mixture from the feed channel side of the membranes to the permeate channel side of the membranes; (c) withdrawing from the permeate conduit a permeate stream comprising the first portion; and (d) withdrawing from the residue conduit as a residue stream a second portion of the feed fluid mixture, said residue stream flowing from the residue outlets into the annular space and out of the assembly through the residue conduit, wherein the annular space and the feed channels are at substantially similar pressures.

31. A fluid separation process using the assembly of claim 21, comprising; (a) introducing a feed fluid mixture into the feed conduit and passing the feed fluid mixture to the feed inlets and along the feed channels; (b) providing a driving force to induce permeation of a first portion of the feed fluid mixture from the feed channel side of the membranes to the permeate channel side of the membranes; (c) passing a sweep stream across the permeate channel side of the membrane; (d) withdrawing from the permeate conduit a permeate stream comprising the first portion; and (e) withdrawing from the residue conduit as a residue stream a second portion of the feed fluid mixture, said residue stream flowing from the residue outlets into the annular space and out of the assembly through the residue conduit, wherein the annular space and the feed channels are at substantially similar pressures.

32. The process of claim 30 or 31, wherein the feed fluid mixture is a gas mixture comprising carbon dioxide from the combustion of carbon-containing fuels.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0067] FIG. 1 is a schematic drawing showing a conventional plate-and-frame membrane module (prior art).

[0068] FIG. 2 is a schematic drawing showing an exemplary plate-and-frame fluid separation membrane module in accordance with the present disclosure.

[0069] FIG. 3 is a schematic drawing showing an exemplary fluid separation assembly with a cross-sectional view of a plate-and-frame fluid separation membrane module contained within a vessel in accordance with the present disclosure.

[0070] FIG. 4 is a schematic drawing showing an exemplary fluid separation assembly containing a plate-and-frame fluid separation membrane module comprising more than one pair of membranes in accordance with the present disclosure.

[0071] FIG. 5 is a schematic drawing showing an exemplary fluid separation assembly containing two plate-and-frame fluid separation membrane modules of FIG. 2 within a vessel in accordance with the present disclosure.

[0072] FIG. 6 is a schematic drawing showing an exemplary fluid separation assembly wherein the feed fluid is introduced directly into the module in accordance with the present disclosure.

[0073] FIG. 7(a)-(b) is a schematic drawing showing exemplary configurations of how fluids can be circulated across the surface of a membrane in a plate-and-frame module.

[0074] FIG. 8(a)-(d) is a schematic drawing further showing different modes for circulating fluids across the surface of a membrane in a plate-and-frame module.

DETAILED DESCRIPTION

[0075] For purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of this disclosure is thereby intended.

[0076] The term fluid as used herein means a gas, vapor, or liquid.

[0077] The term fluid separation as used herein refers to molecular separations that can be carried out m three different modes: (1) gas separation (membrane is in contact with a gas or vapor phase on both sides of the membrane), (2) hydraulic permeation (membrane is in contact with a liquid or supercritical phase on both sides of the membrane), and (3) pervaporation (membrane is in contact with a liquid or supercritical phase on one side of the membrane and with a gas vapor phase on the other side of the membrane). The membrane materials described herein can hi used in any one of the fluid separation modes.

[0078] FIG. 2. depicts an embodiment, of a plate-and-frame fluid separation membrane module, 200. Module 200 comprises a housing, 202, that is preferably made of a lightweight material. The module housing comprises a first end plate, 204, at the top of the module and a second end plate, 206 at the bottom of the module. A plurality of membranes, 208a-e, are contained within the module between the first and second endplates, 204 and 206.

[0079] The housing, 202, is adapted to have an open face or side that allows a feed fluid (from the annular/interior space of the vessel) to enter into the module. FIG. 2 shows the feed side of membranes 208a-e, in which the feed inlets (not shown) are located, where they are exposed to the feed fluid.

[0080] The module also comprises a residue conduit/manifold, 210, a permeate conduit/manifold, 212, and a sweep conduit/manifold, 214. The residue manifold, 210, extends beyond the module and is in fluid-transferring communication with the feed channels (not shown) within the module. The permeate manifold, 212, also extends beyond the module and is in fluid-transferring communication with the permeate channels (not shown). A sweep conduit, 214, is located on the other side of the module opposite the permeate manifold, 212. Sweep conduit 214 is also in fluid-transferring communication with the permeate channels (not shown) within the module.

[0081] A basic embodiment of an assembly of the present disclosure is shown in FIG. 3. Referring to this figure, the assembly, 300, comprises vessel, 302, generally indicated by the dashed lines. The vessel comprises a shell, 304, a feed conduit, 306, a permeate conduit, 308, and a residue conduit, 310. The conduits enable a fluid to flow between environments outside assembly 300, such as pipes, and into assembly 300. Although not shown in this particular embodiment, in other embodiments, vessel, 302, may further comprise at least one removable head.

[0082] The vessel, 302, encloses an annular space, 312, which contains a plate-and-frame fluid separation membrane module, 314. The module comprises a first end plate, 316, and a second end plate, 318. End plates 316 and 318 are part of a housing that encloses a pair of membranes, first membrane, 320, and a second membrane, 322. First and second membranes, 320 and 322, are flat-sheet composite membranes having selective layers, spacers, support layers, coating layers, and the like.

[0083] A permeate channel, 330, runs the length of the module and is connected to and in fluid-transferring communication with the permeate conduit, 308. In this embodiment, only one side of the permeate channel is open, while the other side is blocked by fluid-tight plate 332. The fluid-tight plate, 332, prevents permeate fluid from leaking and mixing with feed or residue fluids in the module. Plate 332 is typically part of the module housing, but may be a separate component attached permanently in place, or may even be removably attached, for example by screw threads, and/or sealed against the tube sheets using gaskets or O-rings.

[0084] Located above the permeate channel, 330, is a first feed inlet, 324, which is in fluid-transferring communication with a first feed flow channel, 326, that is formed in the space between first end plate 316 and first membrane 320. Similarly, located below the permeate channel, 330, is a second feed inlet, 328, that is in fluid-transferring communication with a second feed flow channel, 336.

[0085] A residue outlet or manifold, 334, is located on the opposite end of the module from the first and second feed inlets, 324 and 326. Residue outlet 334 is connected to and is in fluid transferring communication with residue conduit 310 of the vessel.

[0086] In operation, a feed fluid, 350, at a pressure of 3.0 bar, for example, enters assembly 300 through feed port 306 and flows into the annular/interior space 312. The feed fluid then passes through first and second feed inlets, 324 and 328, and flows down first and second feed channels, 326 and 336, respectively.

[0087] A permeating component in the feed fluid mixture permeates first and second membranes, 320 and 322, and passes into permeate channel 330. The permeate fluid, 352, then exits the assembly through permeate conduit 308. Non-permeating components in the feed fluid mixture continue down first and second feed flow channels 326 and 336 and get collected in residue outlet/manifold 334. The residue fluid, 354, then exits the assembly through residue port 310.

[0088] The pressure inside the feed channels, 326 and 336, is a little less than 3.0 bar at the feed end and about 2.9 bar at the residue end. This pressure compresses the permeate channel, 330, and pushes against first and second end plates, 316 and 318, with a pressure of 2.9 to 3.0 bar. However, this pressure is counterbalanced by the outside pressure of 3.0 bar, so the net pressure across the end plates is only 0.1 to 0.0 bar. Advantageously, this design allows for low cost, low weight materials, such as plastic or aluminum to be used to construct the membrane module. This is a very substantial advantage since the cost of these lightweight membrane assemblies is low. This makes it economical to open up the pressure vessel and remove and replace membrane modules/elements as compared to the integrated module design of the type shown in FIG. 1, which is a far more laborious and expensive operation.

[0089] Another embodiment of an assembly of the present disclosure is shown in FIG. 4. The assembly, 400, is similar that the assembly, 300, shown in FIG. 3, but with additional pairs of membranes, 422a-d, between first and second end plates, 416 and 418, in the module, 414. Module 414 is shown as a counterflow unit with a pressurized feed fluid, 440, entering through a feed conduit, 406, and flowing into the annular space, 412, of vessel, 402 (the shell of the vessel is indicated by the dashed lines). From annular space, 412, the feed fluid passes into module 400 through feed inlets, 424a-e, and down feed channels, 426a-e. A residue stream, 446, leaves at a slightly lower pressure through residue outlets, 432a-e, and out of the assembly, 400, via the residue conduit, 410.

[0090] The permeate gas, 442, travels down permeate channels, 430a-d, through the open end (the end is blocked by fluid-tight plates 433a-d), and eventually leaves assembly, 400, at a lower pressure through the permeate conduit, 408. The forces on this unit are small. In the assembly, the permeate and residue gas streams passing across the membrane are collected by simple manifold units, 448 and 434, respectively, into a single stream that leaves through the residue and permeate conduits. The arrangement of these conduits is a simple mechanical design issue and slightly different arrangements may be used depending on the nature of the separation being performed.

[0091] The counterflow design with permeate fluid flowing counter to the feed is the most efficient membrane separation operating mode, but membrane modules using counterflow are mechanically difficult to seal. Crossflow modules in which the feed, and permeate gas flows move at right angles to each other are easier to seal. Because the increase in efficiency offered by the counterflow design is often relatively small, this type of module is often preferred. As discussed in greater detail below, both designs, and others, are within the scope of the present invention.

[0092] An embodiment of an assembly containing two plate-and-frame fluid separation membrane modules is shown in FIG. 5. The assembly, 500, comprises a vessel, 502, having a shell, 504, which forms an annular space, 512. At the top of vessel 502 is a removable head, 522. The vessel, 500, also comprises a feed conduit, 506, two permeate conduits, 508a-b (one for each module), two sweep conduits, 550a-b (one for each module), and two residue conduits (not shown). Vessel 500 contains modules 200a and 200b, which are the same as the modules discussed above in FIG. 2.

[0093] An alternative embodiment of an assembly where a feed fluid is introduced directly into the module is shown in FIG. 6, Referring to this figure, the assembly, 600, comprises vessel, 602, generally indicated by the dashed lines. The vessel comprises a shell, 604, a feed manifold or conduit, 610, a permeate conduit, 608, and a residue conduit, 606. The conduits enable a fluid to flow between environments outside assembly 600, such as pipes, and into assembly 600. Although not shown in this particular embodiment, in other embodiments, vessel, 602, may further comprise at least one removable head.

[0094] The vessel, 602, encloses an annular space, 612, which contains a plate-and frame fluid separation membrane module, 614. The module comprises a first end plate, 616, and a second end plate, 618. End plates 616 and 618 are part of a housing that encloses a first membrane, 620, and a second membrane, 622. First and second membranes, 620 and 622, are flat-sheet composite membranes having selective layers, spacers, support layers, coating layers, and the like.

[0095] A permeate channel, 630, runs the length of the module and is connected to and in fluid-transferring communication with the permeate conduit, 608. In this embodiment, only one side of the permeate channel is open, while the other side is blocked by fluid tight plate 632.

[0096] Located above the permeate channel, 630, is a first feed inlet, 660, which is in fluid-transferring communication with a first feed flow channel, 626, that is formed in the space between first end plate 616 and first membrane 620. Similarly, located below the permeate channel, 630, is a second feed inlet, 662, that is in fluid-transferring communication with a second feed flow channel, 636. Both feed inlets are connected to and in fluid-transferring communication with the feed conduit or manifold, 610.

[0097] A first and a second residue outlet, 626 and 628, are located on the opposite end of the module from the first and second feed inlets, 660 and 662. Residue outlets 626 and 628 are in fluid-transferring communication with the annular space, 612, within the vessel, 602. The annular space is in fluid-transferring communication With the residue conduit, 606.

[0098] In operation, a feed fluid, 650, enters assembly 600 through feed conduit 610 and flows into the first and second feed inlets, 660 and 662, and passes down first and second feed channels, 626 and 636, respectively.

[0099] A permeating component in the feed fluid mixture permeates first and second membranes, 620 and 622, and passes into permeate channel 630. The permeate fluid, 652, then exits the assembly through permeate conduit 608. Non-permeating components in the feed fluid mixture continue down first and second feed flow channels 626 and 636 and exit the module via first and second residue outlets, 626 and 628, and get collected in the annular space, 612. The residue fluid, 654, then exits the assembly through residue conduit 606.

[0100] FIG. 7(a)-(b) is a schematic drawing illustrating how fluids, particularly gases, can he circulated across the surface of a membrane in a plate-and-frame module. For simplicity, only a single membrane module, 700a-b, is shown. An actual assembly might contain as many as 100 plates stacked one on top of the other. In the figure shown, a feed gas, 702a-b, containing 10% CO.sub.2, for example, in nitrogen flows at a pressure of 2 bar across one side of the membrane, 703a-b. Air, 704a-b, at a pressure of 1 bar is circulated across the other side of the module. The gas streams flow in a straight path through the module across the surface of the membrane so parasitic pressure drops are small. Fabric netting spacers (not shown) are used to maintain the feed and permeate channels open. This arrangement allows large volumes of low pressure gas to pass in and out of the module while generating a minimal parasitic pressure drop. This is a major advantage of plate-and-frame modules.

[0101] FIG. 7(a) shows the operation of the module, 700a, in countercurrent mode with the feed gas, 702a, and the sweep gas, 704a, flowing counter to each other. FIG. 7(b) shows the operation of the module, 700b, in cross-flow mode with the feed gas, 702b, and sweep gas, 704b, flowing at right angles to each other. Countercurrent mode modules are more efficient separation devices than crossflow units. But it is generally harder to make, these modules leak free than crossflow modules. Fortunately, the difference between the two operating modes does not become large until the stage cut of the permeate component reaches more than 50% (stage cut is the fraction of the component in the feed gas that passes, into the permeate). Although both operating modes are contemplated in this disclosure, cross-flow modules are normally preferred.

[0102] FIG. 8(a)-(d) is a schematic drawing further showing different modes for circulating fluids across the surface of a membrane in a plate-and-frame module. The two simplest designs, illustrated in FIG. 8(a)-(b), are the conventional crossflow (FIG. 8(a)) and conventional counterflow (FIG. 8(b)) module. Both of these designs only require three conduits to each membrane module assembly, a feed conduit at the highest pressure, a residue conduit at a very slightly lower pressure, and a permeate conduit usually at a lower pressure. In these operating modes, feed components in a feed mixture, 801a-b, with the highest membrane permeance preferentially permeate through the membranes, 802a-b. The residue fluid, 804a-b, is then depleted in these components and the permeate fluid, 803a-b, is enriched in these components.

[0103] Two sweep modes of operation are also shown in FIG. 8(c) (crossflow sweep) and FIG. 8(d) (counterflow sweep). In these modules, a sweep fluid, 805c-d, is introduced on the permeate side of the membrane. A flow of permeating components, 803c-d, from the feed to the sweep and from the sweep to the feed gas is then possible. The driving force for permeation through the membrane is the partial pressure difference across the membrane. If the feed fluid, 801c-d, and the sweep fluid, 805c-d, have different compositions, a flow across the membrane, 802c-d, can occur even when both fluids have the same pressure. An example of this type of separation is the permeation of CO.sub.2 from flue gas (10% CO.sub.2 in nitrogen) into an air sweep at the same pressure (20% oxygen in nitrogen). Even when both gas streams are at atmospheric pressure, a flow of CO.sub.2 into the air sweep and O.sub.2 into the flue gas will occur. However, because CO.sub.2 is 10 to 30 times the permeance of oxygen, most of the CO.sub.2 in the flue gas can be removed into the air sweep before a significant amount of the oxygen is dost to the flue gas, which is vented as a residue stream, for example as in 804c-d.

[0104] Although, in principle, the assemblies described herein can be applied to a wide variety of membrane fluid separations, they are particularly well-suited to processes where parasitic pressure drops are a problem, or where sweep operation on the permeate side of the membrane is needed.

[0105] Parasitic pressure drops are important in gas separation applications, such as the removal of CO.sub.2 from flue gas power plants or oxygen from air. The cost of generating the pressure required to create the pressure difference across the membrane is a large fraction of the cost of the process. For this reason, feed pressures are low or the process may use a vacuum on the permeate side of the membrane. In these applications, parasitic pressure drops of even a few psi can significantly affect the economics of the process.

[0106] Another application for the assemblies described herein is pervaportion or vapor separation applications where the feed fluid is at 1-3 bara, but the permeate side is at a low pressure of 0.01 to 0.1 bar. In these separations, it is very important to maintain the permeate vacuum pressure low and parasitic pressure drops on the permeate side very significantly change the pressure ratio, and hence the separation achieved by the membrane.

[0107] A further application for the assemblies is for separations involving a sweep operation in which fluids are circulated on both side of the membrane. This type of operation is not common, but many examples are known and described in the art, such as the dehydration, of natural gas, separation of organic mixtures by pervaporation, separation of oxygen/nitrogen from air, dehydration of organic mixtures by pervaporation, and carrier facilitated separation of ions from solution.