WO2021245271A1 - Éléments de filtration à membrane - Google Patents

Éléments de filtration à membrane Download PDF

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Publication number
WO2021245271A1
WO2021245271A1 PCT/EP2021/065065 EP2021065065W WO2021245271A1 WO 2021245271 A1 WO2021245271 A1 WO 2021245271A1 EP 2021065065 W EP2021065065 W EP 2021065065W WO 2021245271 A1 WO2021245271 A1 WO 2021245271A1
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WO
WIPO (PCT)
Prior art keywords
membrane
spiral wound
inches
permeate
membrane element
Prior art date
Application number
PCT/EP2021/065065
Other languages
English (en)
Inventor
Mariusz GRZELAKOWSKI
Andrew David SMITH
Prakash Patel
Marshall Dean BREDWELL
Yan Zhang
Original Assignee
Applied Biomimetic A/S
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by Applied Biomimetic A/S filed Critical Applied Biomimetic A/S
Publication of WO2021245271A1 publication Critical patent/WO2021245271A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D63/00—Apparatus in general for separation processes using semi-permeable membranes
    • B01D63/10—Spiral-wound membrane modules
    • B01D63/103—Details relating to membrane envelopes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/14—Ultrafiltration; Microfiltration
    • B01D61/18—Apparatus therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D63/00—Apparatus in general for separation processes using semi-permeable membranes
    • B01D63/10—Spiral-wound membrane modules
    • B01D63/107—Specific properties of the central tube or the permeate channel
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/52—Polyethers
    • B01D71/521—Aliphatic polyethers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/52—Polyethers
    • B01D71/521—Aliphatic polyethers
    • B01D71/5211—Polyethylene glycol or polyethyleneoxide
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/52—Polyethers
    • B01D71/522—Aromatic polyethers
    • B01D71/5222—Polyetherketone, polyetheretherketone, or polyaryletherketone
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/52—Polyethers
    • B01D71/522—Aromatic polyethers
    • B01D71/5223—Polyphenylene oxide, phenyl ether polymers or polyphenylethers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2313/00—Details relating to membrane modules or apparatus
    • B01D2313/14—Specific spacers
    • B01D2313/146—Specific spacers on the permeate side
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2325/00—Details relating to properties of membranes
    • B01D2325/20—Specific permeability or cut-off range

Definitions

  • the present invention concerns membrane filtration elements. More particularly, but not exclusively, this invention concerns improved spiral wound membrane elements comprising highly permeable membranes with reduced hydraulic permeate flow restrictions thus leading to increased permeate flow.
  • Spiral-wound membrane elements have been utilized in the field of membrane filtration for many years. Such elements use a tangential or cross flow filtration method and have been used in the treatment of wastewater, the desalination of brackish water and seawater, biotech/pharma applications such as protein concentration or the removal of impurities such as endotoxins and antibiotics and protein concentration and applications such as, but not limited to, the dairy field applications including milk/whey protein concentration. Such elements can also be used for the concentration and filtration of plant proteins, enzymes and other molecules produced during life science manufacturing such as antibodies.
  • MF microfiltration
  • UF ultrafiltration
  • RO reverse osmosis
  • Spiral-wound elements are usually constructed in a similar way across all applications and membrane types.
  • a typical spiral wound element construction comprises a membrane, a permeate carrier, a feed spacer, a permeate tube, adhesives and the outer wrap/shell.
  • the membrane sheets are glued to form membrane envelopes that contain a permeate spacer or carrier, which ensures that the permeate is transported to a perforated central permeate collector.
  • the membrane sheet is folded in half (face to face) and bonded (back to back) with permeate carrier inserted inside or applied to the surface of the membrane envelope forming the element leaf.
  • the length of the leaf is thus usually about half the length of the membrane sheet.
  • the spiral module is constructed by attaching a number of properly glued membrane envelopes to the central permeate collector, with feed spacers in between to allow the passage of the feed flow.
  • the envelopes and feed spacers are then rolled such that a spiral is formed.
  • an anti-telescope device When the spiral wound membrane element is placed inside a pressure vessel housing, at the outlet end of each spiral, an anti-telescope device is placed to prevent the pressure of the liquid from deforming the membrane shape (in desalination or nanofiltration applications).
  • the anti-telescoping function is generally served by the connectors of the permeate tubes between a plurality of spiral elements in the pressure vessel.
  • either the permeate or the concentrate (or both) may be the desired end product.
  • the present inventors have found that the incorporation of high permeability membranes (such as polyetheramine-based membranes) in the standard spiral element design leads to very little or no improvement of the permeate output and exposes the inefficiencies of the standard design.
  • the present invention seeks to mitigate this problem by altering the design of the spiral wound element to reduce hydraulic permeate flow restrictions, thus allowing to take advantage of increased membrane element permeability provided by a high permeability membrane.
  • the present invention provides a spiral wound membrane element comprising a permeate collector to which are mounted a plurality of membrane envelopes; wherein each membrane envelope comprises a membrane and a permeate carrier; wherein the permeate carrier is in fluid communication with the permeate collector; and wherein the length of the membrane envelope is less than 35 inches.
  • a spiral wound membrane element comprising a permeate collector to which are mounted a plurality of membrane envelopes; wherein each membrane envelope comprises a membrane and a permeate carrier; wherein the permeate carrier is in fluid communication with the permeate collector; and wherein the length of the membrane envelope is less than 35 inches.
  • a protein concentration system comprising a spiral wound membrane element of an embodiment of the present invention.
  • a method of purifying an aqueous solution, suspension or colloid using a spiral wound membrane element of an embodiment of the present invention is provided.
  • a system for purifying an aqueous solution, suspension or colloid comprising a spiral wound membrane element of an embodiment of the present invention.
  • a method of manufacturing a spiral wound membrane element of an embodiment of the present invention comprising the steps of: a. assembling a membrane envelope comprising a solid high permeability membrane and a permeate carrier; b. mounting a plurality of said membrane envelopes on a permeate collector such that the permeate carriers are in fluid communication with the permeate collector; c. winding the membrane envelopes around to the permeate collector to form the spiral wound membrane element.
  • a method of manufacturing a spiral wound membrane element comprising: modifying an original spiral wound membrane element design in order to reduce hydraulic restriction on the permeate side of said spiral wound membrane element by: (i) reducing the length of the membrane envelope whilst ensuring that the membrane surface area available for filtration remains essentially the same or increases, by increasing the number of membrane envelopes within said spiral wound membrane element; and/or (ii) increasing the thickness of the permeate carrier; to produce a new spiral wound element design; wherein the spiral wound membrane element comprises a permeate collector to which are attached a plurality of membrane envelopes; wherein the membrane envelopes comprise a membrane and a permeate carrier; wherein the permeate carrier is in fluid communication with the permeate collector; and making a spiral wound membrane element according to the new spiral wound membrane element design.
  • a method of ultrafiltration or microfiltration comprising a step of using a spiral wound membrane element according to an embodiment of the present invention.
  • an ultrafiltration or microfiltration system comprising a spiral wound membrane element according to an embodiment of the present invention.
  • Figure 1 is a graph showing output of a spiral wound membrane element according to an embodiment of the invention comprising 18 membrane envelopes compared to a spiral wound membrane elements comprising 12 membrane envelopes, wherein output is expressed in liters per minute (LPM - Figure 1A), gallons per foot squared per day per pound per square inch (GFD/psi - Figure IB) and total processed volume in liters (Figure 1C).
  • LPM - Figure 1A gallons per foot squared per day per pound per square inch
  • GFD/psi - Figure IB total processed volume in liters
  • Figure 2A is a graph showing the relationship between the number of membrane envelopes and membrane element flux values as measured in GFD/psi.
  • Figure 2B is a graph showing the relationship between the number of membrane envelopes and membrane element output as measured in kg/min.
  • Figure 3 shows a schematic view of part of a spiral wound membrane element according to an embodiment of the invention in (a) an unwound and (b) partially wound state.
  • Figure 4 shows a schematic side view of a membrane envelope of the spiral wound membrane element of Figure 3.
  • Figure 5 shows the setup of a skid for performing a pure water flux test (PWF) or Whey Protein Concentrate run using a spiral wound membrane element.
  • PWF pure water flux test
  • Whey Protein Concentrate run using a spiral wound membrane element.
  • FIG. 3 shows a schematic view of part of a spiral wound membrane element 1.
  • the spiral wound membrane element 1 is shown prior to winding in Fig. 3(a) and partially wound in Fig. 3(b).
  • a plurality of membrane envelopes 4 are attached at a proximal edge region 4a to an elongate tubular permeate collector 2.
  • a plurality of feed spacers 6 are attached at a proximal edge region (not shown) to the permeate collector.
  • Each membrane envelope 4 and feed spacer 6 extends along the majority of the length of the permeate collector 2.
  • Each feed spacer 6 is located in-between two membrane envelopes 4 to provide an alternating pattern of membrane envelopes 4 and feed spacers 6. For clarity, only one membrane envelope 4 and one feed spacer 6 membrane are shown in Fig.
  • Figure 4 shows a schematic side view of part of a membrane envelope 4 mounted to the permeate collector 2.
  • the membrane envelope 4 comprises a permeate carrier sheet 8 attached at a proximal edge region 8a to the permeate collector 2.
  • the membrane envelope 4 also comprises a membrane sheet 10 which surrounds the permeate carrier sheet 8.
  • At the distal end of the membrane envelope 4 is a distal sealant line 12.
  • Other sealant lines may be found along the radial edges of the membrane envelope 4.
  • the active length L of the membrane envelope 4 is the distance between the point of attachment of the membrane envelope 4 to the permeate collector 2 (i.e. the outermost limit of proximal edge region 4a) and the (inner edge of the) distal sealant line 12.
  • feed solution enters the spiral wound membrane element 1 and passes over the outside of the membrane envelope 4.
  • Permeate passes from the feed solution through the membrane sheet 10 to the permeate carrier sheet 8 and then travels along the permeate carrier sheet 8 to the permeate collector 2, from which it then leaves the spiral wound membrane element 1.
  • Feed spacers 6 maintain a gap between adjacent membrane envelopes 4 to allow feed solution to reach the surface of each envelope.
  • the sealant lines (including distal sealant line 12) bond the membrane sheet 10 together to form the membrane envelope 4.
  • the present invention is based on the surprising observation that reducing the length of the membrane envelopes in a spiral wound membrane element, optionally in combination with increasing the number of membrane envelopes (also known as membrane leaves) in the membrane element; or modifying the thickness/structure of the permeate carrier, optionally in combination with an increase in membrane leaf length and a reduction in the number of leaves, increases the overall output of the membrane element (either/both permeate or concentrate, depending on the desired output) when compared with an element that has not been so modified.
  • the advantageous modifications described herein reduce hydraulic restriction on the permeate side of the membrane element, especially within the context of the use of a high permeability membrane.
  • the present disclosure includes spiral wound membrane elements according to the present invention which have reduced hydraulic restriction on the permeate side of the membrane element. Reduced hydraulic restriction on the permeate side of the membrane element may be demonstrated by increased pure water flux.
  • the membrane element configuration of the present invention also leads to other advantages. For example, cleaning of the membrane elements in between runs can be achieved more quickly, since the rate of flow of cleaning fluid through the element is increased. Accordingly the clean-in-place (CIP) cycle of the improved elements of the invention is shorter.
  • CIP clean-in-place
  • a spiral wound membrane element comprises a permeate collector.
  • the permeate collector comprises a plastic tube (e.g. a tube made of, for example, acrylonitrile-butadiene-styrene, polyvinyl chloride, polysulfone, poly(phenylene oxide), polystyrene, polypropylene, polyethylene or the like).
  • a plurality of holes are formed in the tube through which permeate can penetrate from the exterior of the tube to the interior of the tube.
  • a plurality of membrane envelopes are mounted on the tube, wherein each membrane envelope comprises a membrane and a permeate carrier.
  • the permeate carrier is in fluid communication with the permeate collector, for example with the interior of the permeate collector via the holes.
  • each membrane envelope abuts the permeate collector such that the permeate carrier is in fluid communication with the interior of the permeate collector, for example via a plurality of said holes, said holes being spaced apart along the longitudinal axis of the permeate collector.
  • Spiral wound membrane elements are usually supplied with a standard diameter, for example 1.8, 2.5, 3.8, 4.3, 5.8, 6.3, 6.4, 7.8, 8, 8.3, 8.4, 9, 10 or 16 inches. Any such standard diameter may be used in the context of any of the embodiments of the spiral wound membrane of the invention.
  • spiral wound membrane elements are usually supplied with a standard length, e.g. about 40 inches, e.g. about 38 inches.
  • any manipulations or alterations of the configuration of a spiral wound membrane element according to the present invention which seek to reduce hydraulic restrictions on the permeate side of the element, such manipulations or alterations should seek to maintain membrane surface area at or very near the membrane surface area of the unmodified membrane element. This is because available membrane surface area is an important criterion determining total output of the element.
  • a spiral wound membrane element of an embodiment of the present invention may be manufactured as follows.
  • the element is formed by concentrically winding a plurality of membrane envelopes and optional feed channel spacer sheet(s) ("feed spacers") about a permeate collection tube.
  • feed spacers feed channel spacer sheet(s)
  • Each membrane envelope preferably comprises two substantially rectangular sections of membrane sheet.
  • the membrane envelope is formed by overlaying membrane sheets and aligning their edges. The sections of membrane sheet surround a permeate channel spacer sheet ("permeate spacer").
  • This sandwich-type structure is secured together, e.g. by sealant, along three edges to form an envelope while a fourth edge, i.e.
  • the "proximal edge” abuts the permeate collection tube so that the inside portion of the envelope and the permeate spacer are in fluid communication with a plurality of openings extending along the length of the permeate collection tube.
  • the membrane envelopes and optional feed spacer(s) are wound or "rolled” concentrically about the permeate collection tube to form a first and second scroll face at opposing ends and the resulting spiral bundle is held in place, such as by tape or other means.
  • Imperial units or their Metric (SI) equivalents may be used. For a given Imperial unit, an equivalent Metric (SI) unit exists.
  • a measurement may be converted into centimetres (cm), using a conversion factor of 2.54, i.e. 1 inch equals 2.54 cm or 25.4 mm.
  • the present invention provides a spiral wound membrane element comprising a permeate collector to which are mounted a plurality of membrane envelopes; wherein the membrane envelopes comprise a membrane and a permeate carrier; wherein the permeate carrier is in fluid communication with the permeate collector and wherein the length of the membrane envelope is less than 35 inches.
  • the length of the membrane envelope is less than 30, less than 25, less than 20, less than 15 inches or less than 10 inches.
  • the length of the membrane envelope may be between 10 and 35 inches, between 10 and 30 inches, between 10 and 25 inches, between 10 and 20 inches or between 10 and 15 inches.
  • the length of the membrane envelope refers to its length within the context of the manufactured spiral wound membrane element.
  • the length of the membrane envelope may refer to the active length of the membrane envelope.
  • the membrane envelope comprises a proximal edge via which the membrane envelope is connected to the permeate collector.
  • the membrane envelope comprises a distal edge (the edge of the membrane envelope furthest from the permeate collector when the spiral wound element is unrolled).
  • the membrane envelope may comprise an axial sealant line.
  • the axial sealant line may be a region in which two regions of the membrane envelope are sealed together (for example using an adhesive) such that permeate cannot pass through that region.
  • the axial sealant line may extend in a direction substantially parallel to the longitudinal axis of the permeate collector when the spiral wound element is unrolled.
  • the axial sealant line may be located in the region of the distal edge of the membrane envelope.
  • the active length of the membrane envelope may be defined as the distance between the proximal edge of the membrane envelope and the axial sealant line of the membrane envelope.
  • the active length refers to the maximum distance available to the permeate to flow along the membrane envelope to the permeate collector.
  • the length of the membrane envelope also thus refers to the length of the membrane envelope available for filtration.
  • the length of the membrane envelope available for filtration may also be referred to herein as the active length.
  • the diameter of the spiral wound membrane element is less than 4 inches, e.g. 1.8, 2.5 or 3.8 inches. In another embodiment of the invention, the diameter of the spiral wound element is about 3.8 inches.
  • the diameter of the spiral wound membrane element is between 4 and 7 inches, e.g. about 6.3 or about 6.4 inches.
  • the diameter of the spiral wound membrane element is between 7 and 10 inches, e.g. about 8, about 8.3 or about 8.4 inches.
  • the number of membrane envelopes is between 8 and 30, between 8 and 28, between 8 and 26, between 8 and 24, between 8 and 22 or between 8 and 20 inclusive.
  • the diameter of the element is at least 4 inches, e.g. between 4 and 7 inches, e.g. 5.8, 6.3, 6.4 inches
  • the number of membrane envelopes is between 8 and 30, between 10 and 30, between 12 and 30, between 14 and 30, between 16 and 28, between 18 and 26 or between 18 and 24 inclusive.
  • the diameter of the element is at least 4 inches, e.g.
  • the number of membrane envelopes is between 16 and 30, or between 16 and 26 inclusive.
  • the diameter of the element is at least 4 inches, e.g. between 4 and 7 inches, e.g. 5.8, 6.3, 6.4 inches
  • the number of membrane envelopes is 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30.
  • the membrane surface area of the element is at least 150, at least 160, at least 170, at least 180, at least 190, at least 195, at least 200, at least 205, at least 210, at least 215, at least 220, at least 225, at least 230, at least 235, at least 240 or at least 250 square feet.
  • the membrane surface area of the element is between 150 and 260, between 170 and 260, between 180 and 260 or between 190 and 260 square feet.
  • references to surface area herein refer to the active surface area, that is the surface area that is available for filtration.
  • the active surface area does not include those parts of the membrane envelope that are not accessible to liquid flows through the element, e.g. those areas of the membrane envelope that are occupied by glue (or adhesive) lines required for the formation of the envelope from the folded membrane. Such areas may be referred to as sealant regions or lines.
  • Suitable sealants for sealing membrane envelopes include urethanes, epoxies, silicones, acrylates, hot melt adhesives and UV curable adhesives. While less common, other sealing means may also be used such as the application of heat, pressure, ultrasonic welding and tape.
  • the membrane envelope may comprise one or more sealant lines, for example an axial sealant line as described above.
  • the diameter of the spiral wound membrane element is less than 4 inches, e.g. between 1.5 and 4 inches, e.g. 1.8, 2.5 or in particular 3.8 inches
  • the number of membrane envelopes is at least 5, e.g. 5, 6, 7, 8, 9 or 10 or between 5-10, 6-10, 6-9, 5-9 or 6-8 inclusive.
  • the length of the membrane envelope is less than 30 inches, less than 25, less than 20 inches or less than 15 inches.
  • the membrane surface area is at least at least 40, at least 50, at least 55, at least, 60, at least 65, at least 70, at least 75, at least 80 or at least 85 square feet.
  • the membrane envelopes (or leaves) comprise a permeate carrier.
  • the function of the permeate carrier is to convey liquid that has permeated through the membrane to the permeate collector.
  • the permeate carrier may be made from any suitable material, for example polyester.
  • a particular example is a tricot fabric woven from epoxy or melamine-coated polyester filaments.
  • the tricot fabric is porous and forms a series of parallel ridges, which keep the membrane leaf from collapsing, separated by grooves on one side of the fabric.
  • the grooves are oriented perpendicular to the central tube to provide less obstructed passages for permeate to flow inwards through the leaves to the central tube.
  • a separate reinforcing or anti-bagging layer may be placed between the membrane sheet and the tricot fabric to help keep the membrane sheet from being pressed into the grooves of the tricot.
  • a permeate sheet carrier may be coated to make its surfaces hydrophilic, with such hydrophilic coating promoting water flow in the permeate channels.
  • the coating may be, for example, a cross-linked polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP) or other chemicals.
  • the thickness of the permeate carrier is between 8 and 25 mil, or between 10 and 20 mil, for example 10, 12, 14, 16, 18 or 20 mil.
  • the thickness of the permeate carrier is 10 to 12 mil, e.g. 10 or 12 mil. In another embodiment, the thickness of the permeate carrier is between 14 and 25 mil, e.g. 14, 16, 18 or 20 mil.
  • Particular examples of permeate carriers that may be used in the context of the present invention include 10 mil and 12 mil permeate carriers. Examples of such permeate carriers are manufactured by Guilford Performance Textiles (Wilmington, NC) and Hornwood, Inc. (Lilesville, NC). Other examples of permeate carriers that may be used in the context of the present invention include 14 mil and 20 mil permeate carriers. An example of a 20 mil permeate carrier is manufactured by Hornwood, Inc. (Lilesville, NC).
  • the permeate carrier has a differential thickness along its length, with the thickness decreasing with increasing (radial) distance from the permeate collection tube.
  • the portion of the permeate carrier furthest from permeate collection tube has a thickness of, for example, 10 mil, with the thickness increasing towards the collection tube, to arrive at a thickness of, for example, 20 mil in the portion of the permeate carrier closest to the permeate collection tube.
  • the increase in the thickness of the permeate carrier from the portion most distal from the permeate collection tube to the portion most proximal to the permeate collection tube may be stepwise, e.g. 10 mil, 12 mil, 14 mil, 20 mil.
  • a permeate carrier having differential thicknesses may be constructed by fusing together sheets of permeate carrier of different thicknesses which are cut to appropriate lengths. The fusing may be achieved via the use of sonic welders.
  • An alternative way to achieve a permeate carrier having differential thicknesses is to deposit (e.g. 3D print) the spacing features onto the back surface of the membrane (i.e. onto the backing fabric), for example using 3D printed spacer technology as described elsewhere herein. Printing of the permeate carrier onto to the back surface of the membrane could also be used in the context of a permeate carrier having a constant thickness.
  • the present invention provides a spiral wound membrane element comprising a permeate collector to which are attached a plurality of membrane envelopes; wherein each membrane envelope comprises a membrane and a permeate carrier; wherein the permeate carrier is in fluid communication with the permeate collector and wherein the thickness of the permeate carrier is at least 14 mil, at least 16 mil, at least 18 mil or at least 20 mil.
  • the thickness of the permeate carrier is between 14 and 30, between 14 and 28, between 14 and 26, between 14 and 24, between 14 and 22, between 14 and 20 mil, between 16 and 30 mil, between 18 and 30 mil or between 20 and 30 mil inclusive.
  • the thickness of the permeate carrier is about 14, about 16, about 18, about 20, about 22 or about 24 mil.
  • the active length of the membrane envelope is more than 35 inches, more than 40 inches, more than 50 inches, more than 60 inches, more than 70 inches, more than 80 inches, more than 90 inches, more than 100 inches, more than 120 inches or more than 140 inches.
  • the diameter of the element may be less than 4 inches, e.g. 3.8 inches; between 4 and 7 inches, e.g. 6.3 or 6.4 inches or between 7 and 10 inches, e.g. 8, 8.3 or 8.4 inches.
  • the thickness of the permeate carrier is between 14 and 22 mil or between 16 and 20 mil, e.g. 20 mil; the diameter of the element is between 7 and 9 inches, e.g. 8, 8.3 or 8.4 inches and the number of membrane envelopes is less than 15, less than 14, less than 13, e.g. 12, 11, 10, 9 or 8.
  • the membrane surface area is at least 250, at least 270, at least 290 or at least 300 square feet and the membrane active length is at least 45, at least 50, at least 60 or at least 70 inches, e.g. 45-80 inches.
  • the thickness of the permeate carrier is between 14 and 22 mil or between 16 and 20 mil, e.g. 20 mil; the diameter of the element is between 4 and 7 inches, e.g. 6.3 or 6.4 inches and the number of membrane envelopes is less than 10, less than 9, e.g. 10, 9, 8, 7, 6 or 5.
  • the membrane surface area is at least 180, at least 190 or at least 200 square feet and the membrane active length is at least 35, at least 40, at least 50, at least 60 or at least 70 inches, e.g. 35-80 inches.
  • the thickness of the permeate carrier is between 14 and 22 mil or between 16 and 20 mil, e.g.
  • the membrane surface area is at least 50 or at least 60 square feet and the membrane active length is at least 30, at least 35, at least 40, at least 50, at least 75 or at least 100 inches, e.g. 35-70 inches.
  • the spiral wound membrane element has a diameter of 6 to 7 inches, e.g. about 6.3 or 6.4 inches, between 16 and 28 membrane leaves, an active membrane length of between about 14 and about 20 inches, a membrane surface area of between 190 and 260 square feet and a permeate carrier thickness of about 10 to about 12 mil.
  • the thickness of the feed spacer may be about 20 to about 31 mil.
  • the spiral wound membrane element has a diameter of 6 to 7 inches, e.g. about 6.3 or 6.4 inches, between 15 and 20 membrane leaves, an active membrane length of between about 15 and about 25 inches, a membrane surface area of between 190 and 260 square feet and a permeate carrier thickness of about 10 to about 12 mil.
  • the thickness of the feed spacer may be about 20 to about 31 mil.
  • the spiral wound membrane element has a diameter of 6 to 7 inches, e.g. about 6.3 or 6.4 inches, between 5 and 9 membrane leaves, an active membrane length of between about 40 and about 80 inches, a membrane surface area of between 190 and 260 square feet and a permeate carrier thickness of about 14 to about 20 mil.
  • the thickness of the feed spacer may be about 20 to about 31 mil.
  • the spiral wound membrane element has a diameter of 3.5 to 4.5 inches, e.g. about 3.8 inches, between 6 and 10 membrane leaves, an active membrane length of between about 11 and about 22 inches, a membrane surface area of between 55 and 90 square feet and a permeate carrier thickness of about 10 to about 12 mil.
  • the thickness of the feed spacer may be about 20 to about 31 mil.
  • the spiral wound membrane element has a diameter of 3.5 to 4.5 inches, e.g. about 3.8 inches, between 2 and 4 membrane leaves, an active membrane length of between about 25 and about 80 inches (e.g. between about 35 and about 80 inches), a membrane surface area of between 50 and 85 square feet and a permeate carrier thickness of about 14 to about 20 mil.
  • the thickness of the feed spacer may be about 20 to about 31 mil.
  • the spiral wound membrane element has a diameter of 7 to 9 inches, e.g. about 8 inches, between 22 and 42 membrane leaves, an active membrane length of between about 14 and about 25 inches, a membrane surface area of between 300 and 420 square feet and a permeate carrier thickness of about 10 to about 12 mil.
  • the thickness of the feed spacer may be about 20 to about 31 mil.
  • the spiral wound membrane element has a diameter of 7 to 9 inches, e.g. about 8 inches, between 20 and 28 membrane leaves, an active membrane length of between about 18 and about 32 inches, a membrane surface area of between 300 and 420 square feet and a permeate carrier thickness of about 10 to about 12 mil.
  • the thickness of the feed spacer may be about 20 to about 31 mil.
  • the spiral wound membrane element has a diameter of 7 to 9 inches, e.g. about 8 inches, between 6 and 15 membrane leaves, an active membrane length of between about 40 and about 120 inches, a membrane surface area of between 300 and 450 square feet and a permeate carrier thickness of about 14 to about 20 mil, e.g. about 20 mil.
  • the thickness of the feed spacer may be about 20 to about 31 mil.
  • the membrane is a high permeability membrane having a pure water permeability of at least at least 1, at least 2, at least 3, at least 4, at least 5 at least 6 or at least 7 GFD/psi. In other embodiments, the membrane has a pure water permeability of at least 8, at least 9, at least 10, at least 12, at least 16, at least 20, at least 25, at least 30, at least 40, at least 50, at least 60, at least 70, at least 80 or at least 100 GFD/psi.
  • the membrane has a pure water permeability of 2-100, 2-80, 2-60, 2-40, 2-30, 2-20, 2-12, 2-10, 7-100, 7-80, 7-60, 7- 40, 7-30, 7-20, 7-12 or 7-10, 8-100, 8-80, 8-60, 8-40, 8-30, 8-20, 8-12 or 8-10 GFD/psi.
  • the membrane has a pure water permeability of 10-100, 12-100, 16-100, 18-100, 20-100, 40-100, 60-100, 80-100, 25-100 or 25-80 GFD/psi.
  • the membrane has a pure water permeability of 2-20, 4-20, 6-20, 2-10, 4-10, 6-10, 2-16, 4-16, 6-16, 2-12, 4-12, 6-12, 8-20, 10-20, 12-20, 14-20, 16-20, 8-10, 10-12, 8-12, 8-16, 10-16, 10-12, 10-18 or 10-20 GFD/psi.
  • permeability of a membrane is also a function of the molecular weight cut off (MWCO) of the membrane and membranes with greater MWCO’s will generally have greater permeability values as measured by pure water flux (PWF).
  • the permeability values (in GFD/psi) disclosed herein are for membranes having a MWCO of less than or equal to 100, less than or equal to 80, less than or equal to 70, less than or equal to 50, less than or equal to 30 or less than or equal to 10 kDa.
  • the membrane is a high permeability membrane having a pure water permeability of at least 20 GFD/psi, e.g. 20-80 GFD/psi and a MWCO value of less than 60 kDa, e.g. 5 to 50 kDa, 5 to 30 kDa, 10 to 50 kDa or 20 to 50 kDa.
  • the membrane is a high permeability membrane having a pure water permeability of at least 25 GFD/psi, e.g. 25-75 GFD/psi and a MWCO value of less than 60 kDa, e.g. 5 to 50 kDa, 5 to 30 kDa, 10 to 50 kDa or 20 to 30 kDa.
  • the membrane is a high permeability membrane having a pure water permeability of at least 30 GFD/psi, e.g. 30-75 GFD/psi and a MWCO value of less than 60 kDa, e.g.
  • the membrane is a high permeability membrane having a pure water permeability of at least 2 GFD/psi, e.g. 2-75, 2-70, 2-50, 2-25, 2-20, 2-10 or 2-5 GFD/psi and a MWCO value of less than 30 kDa, e.g. 5 to 30 kDa.
  • a high permeability membrane according to the invention may be a membrane with a stated MWCO of 5 kDa and a pure water permeability of 1-7 GFD/psi, for example about 3 GFD/psi.
  • a high permeability membrane according to the invention may be a membrane with a stated MWCO of 10 kDa and a pure water permeability of 3-10 GFD/psi, for example about 5 or 7 GFD/psi.
  • a high permeability membrane according to the invention may be a membrane with a stated MWCO of between 5 and 30 kDa and a pure water permeability of 3 to 20, 3 to 10 or 3 to 7 GFD/psi, for example about 5 or 7 GFD/psi.
  • a high permeability membrane according to the invention may be a membrane with a stated MWCO of between 5 and 30 kDa and a pure water permeability of 7 to 70, 8 to 70, 10 to 70, 20 to 70 or 25 to 70 GFD/psi.
  • a high permeability membrane according to the invention may be a membrane with a stated MWCO of between 10 and 30 kDa and a pure water permeability of 7 to 70, 8 to 70, 10 to 70, 20 to 70 or 25 to 70 GFD/psi.
  • a high permeability membrane according to the invention may be a membrane with a stated MWCO of 10 and a pure water permeability of at least 7, at least 8 or at least 10 GFD/psi, for example 7 to 30, 7 to 25, 7 to 20, 8 to 25, 8 to 20, 10 to 25 or 10 to 20 GFD/psi.
  • a high permeability membrane according to the invention may be a membrane with a stated MWCO of between 20 and 100 kDa and a pure water permeability of at least 50 GFD/psi, e.g. 50 to 100 GFD/psi.
  • a high permeability membrane according to the invention may be a membrane with a stated MWCO of between 20 and 30 kDa and a pure water permeability of at least 7, at least 8, at least 10 or at least 20 GFD/psi, e.g. 20 to 80 or 50 to 80 GFD/psi.
  • the membrane is a high permeability membrane selected from the group consisting of: (i) a membrane having a pure water permeability of at least 20 GFD/psi, e.g. 20-25 GFD/psi and a MWCO of about 10 kDa; (ii) a membrane having a pure water permeability of at least 40 GFD/psi, e.g.
  • membrane permeability values disclosed herein are measured using a pure water flux (PWF) test carried out at an ambient temperature of 20°C (68°F) using clean water (RO, ultra-pure water). Pure water flux tests are carried out using Amicon (EMD Millipore, 51241
  • PWF pure water flux
  • the high permeability membrane has a lack of micro and macro voids as visualised by scanning electron microscopy (SEM) of a cross section of the membrane.
  • SEM scanning electron microscopy
  • the high permeability membrane comprises a portion of the membrane that is free from micro and macro voids, as visualised by SEM of a cross section of the membrane.
  • that portion comprises at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80% or at least 90% of the membrane.
  • a high permeability membrane has improved pore size control and regular pore size distribution.
  • the high permeability membrane is an ultrafiltration (UF) membrane.
  • UF membranes have a pore size in the range of 0.001- 0.1 pm, and a molecular weight cut-off (MWCO) in the range of 1-500 kDa.
  • the MWCO value refers to the approximate molecular weight (MW) of a dilute globular solute (i.e., a typical protein) which is 90% retained by the membrane.
  • UF membranes possess a retention rate which allows for further rejection of all bacteria, viruses and macromolecules. Rejection (or not) of a particular protein by a UF membrane will, of course, depend on the exact MWCO of the UF membrane and the MW of the protein in question.
  • the MWCO of a UF membrane can be measured by passing molecules with a known molecular weight through the membrane (i.e. using markers such as polyethylene glycol or dextran).
  • UF membranes with specified MWCO values are available from various commercial suppliers, e.g. Koch Membrane Systems (Wilmington, MA, USA), Microdyn-Nadir (Goleta, CA, USA), Toray (Poway, CA, USA), Alfa Laval (Richmond, VA, USA) and Synder Filtration (Vacaville, CA, USA).
  • the high permeability membrane is a UF membrane having a MWCO value in the range of from 1 to 500 kDa, 3 to 300 kDa, 5-200 kDa or 10-100 kDa.
  • the high permeability membrane is a UF membrane having a MWCO value in the range of from 1 to 300 kDa, 1 to 200 kDa, 1 to 100 kDa, 1 to 70 kDa, 3 to 70 kDa, 1 to 50 kDa, 5 to 500 kDa, 10 to 500 kDa, 20 to 500 kDa, 50 to 500 kDa, 10 to 50 kDa, 10 to 100 kDa, 5 to 80 kDa or 100 to 500 kDa.
  • the high permeability membrane is a UF membrane having a MWCO of 1, 3, 5, 10, 20, 30, 50, 100, 200, 300, 400, 500 or 800 kDa.
  • the high permeability membrane is a UF membrane having a MWCO in the range of about 10 to about 50 kDa, e.g. about 10 to about 30 kDa.
  • the high permeability membrane is a UF membrane having a MWCO in the range of about 10 to about 50 kDa, e.g. about 10 to about 30 kDa, and a permeability of at least 20 GFD/psi (e.g.
  • the high permeability membrane is a UF membrane having a pore size in range of from 0.001-0.1 pm, 0.005-0.1 pm, 0.01-0.1 pm, 0.05 to 0.1 pm, 0.001-0.08 pm, 0.001-0.05 pm, 0.001-0.01 pm or 0.001-0.005 pm.
  • UF membranes typically operate between 5-120 PSI (3.4-8.3 bar) and are dependent on transmembrane pressure to drive the separation process. UF membranes are most applicable for separation in the food and dairy, biotech, water treatment (especially water pre-treatment prior to desalination for the production of drinking water) and pharmaceutical industries, as well as in the automotive industry for cathodic paint recovery.
  • the high permeability UF membrane is a DairySepTM UF membrane as manufactured by Applied Biomimetic, Gaithersburg, MD, 20878, USA (https://www.appliedbiomimetic.com/ab-dairysep-membrane/).
  • Such membranes are polysulfone (PS) based membranes are characterized by having extremely high pure water flux values (e.g. at least 5, at least 10, at least 20, at least 25 or at least 30 GFD/psi) and narrow MWCO values, and which may be supplied with a range of MWCO’s, e.g. 5, 8, 10, 20, 30, 50, 100 or 200 kDa, especially 5, 8, 10, 20, 30 or 100 kDa.
  • PS polysulfone
  • the spiral wound elements are of particular use in the context of the dairy industry, for applications such as whey protein concentration, whey protein isolation, casein or whey fractionation, milk protein fractionation or milk protein concentration.
  • the spiral wound elements of the present invention are of particular use in the concentration and fractionation of plant-derived proteins (e.g. in the production of plant-derived milks), the concentration or fractionation of proteins such as enzymes and fermentation-derived proteins and the concentration or fractionation of proteins derived from animal sources such as bovine, porcine, avian proteins etc.
  • the present invention includes methods for the concentration, fractionation or isolation of: milk-derived proteins such as whey and casein; plant-derived proteins and proteins such as enzymes and fermentation-derived proteins, wherein said methods utilize a spiral bound membrane element according to the present invention.
  • the present invention includes methods for the concentration, fractionation or isolation of: milk-derived proteins such as whey and casein; plant- derived proteins and proteins such as enzymes and fermentation-derived proteins, wherein said methods utilize a spiral bound membrane element according to the present invention.
  • the present invention also includes systems for the concentration, fractionation or isolation of: milk-derived proteins such as whey and casein; plant- derived proteins such as soy, coconut, almond, rice and oat-derived protein and proteins such as enzymes and fermentation-derived proteins, wherein said systems comprise a spiral bound membrane element according to the present invention.
  • milk-derived proteins such as whey and casein
  • plant- derived proteins such as soy, coconut, almond, rice and oat-derived protein and proteins such as enzymes and fermentation-derived proteins
  • the high permeability membrane is a microfiltration (MF) membrane.
  • MF microfiltration
  • the high permeability membrane is an MF membrane having a MWCO value of at least 100 kDa, at least 500 kDa, at least 800 kDa or at least 1000 kDa.
  • the high permeability membrane is a MF membrane having a MWCO value in the range of from 100 kDa to 1000 kDa, 200 to 1000 kDa, 500 to 1000 kDa or 800 to 1000 kDa.
  • the high permeability membrane is an MF membrane having a molecular size cut off in the range of from 0.08 to 0.2 pm, 0.1 to 0.2 pm, 0.15 to 0.2 pm, 0.08 to 0.15 pm or 0.08 to 0.1 pm.
  • the high permeability membrane is an MF membrane having a size cut off of at least 800 kDa, at least 0.1 pm or at least 0.2 pm.
  • MF membranes with specified cut-off values are available from various commercial suppliers, e.g. Koch Membrane Systems (Wilmington, MA, USA), Synder Filtration (Vacaville, CA, USA).
  • MWCO Molecular weight cut-off
  • Molecular weight cut-off for a particular membrane is defined as the molecular weight of the solute where 90% rejection in observed.
  • the high permeability membrane is a nanofiltration (NF) membrane.
  • Nanofiltration is a separation process characterized by organic, thin- film composite membranes with a pore size range of 0.1 to 10 nm. Unlike reverse osmosis (RO) membranes, which reject all solutes, NF membranes can operate at lower pressures and offer selective solute rejection based on both size and charge.
  • RO reverse osmosis
  • nanofiltration membranes allow water and some salts to pass through the membrane while retaining multivalent ions, low molecular weight molecules, sugars, proteins, and other organic compounds.
  • the high permeability membrane is a reverse osmosis (RO) membrane.
  • RO reverse osmosis
  • the membrane is used to remove ions, unwanted molecules and larger particles from drinking water.
  • an applied pressure is used to overcome osmotic pressure.
  • Reverse osmosis can remove many types of dissolved and suspended chemical species as well as biological ones from water. The result is that the solute is retained on the pressurized side of the membrane and the pure solvent is allowed to pass to the other side.
  • this type of membrane should not allow large molecules or ions through the pores, but should allow smaller components of the solution (such as solvent molecules, i.e., water) to pass freely.
  • Reverse osmosis differs from filtration in that the mechanism of fluid flow is by osmosis across a membrane.
  • the predominant removal mechanism in membrane filtration is straining, or size exclusion, whereas RO instead involves solvent diffusion across a membrane that is either non-porous or uses pores 0.001 micrometres in size.
  • the predominant removal mechanism is based on differences in solubility or diffusivity, and the process is dependent on pressure, solute concentration, and other conditions.
  • suitable membrane forming polymers include for example: cellulose acetate/triacetate; polyamide, including aromatic polyamide; polypiperazine; polybenzimidazoline; polyol, including polyphenol; polyacrylonitrile (PAN); polyethersulfone (PES); polysulfone (PS); poly(phthalazinone ether sulfone ketone) (PPESK); poly(vinyl butyral); Polyvinylidene fluoride (PVDF); poly(tetrafluoroethylene) (PTFE); polypropylene (PP); polyethylene (PE), polyetheretherketone (PEEK), polyimide (PI) and polyetherimide (PEI).
  • PAN polyacrylonitrile
  • PES polyethersulfone
  • PS polysulfone
  • PPESK poly(phthalazinone ether sulfone ketone)
  • PVDF Polyvinylidene fluoride
  • PVDF poly(tetrafluoroethylene)
  • PP polyprop
  • the membrane-forming polymer used for making the high permeability membrane is any membrane-forming polymer, which is not reactive with the water-soluble polyetheramine.
  • Suitable polymers which are not reactive with a water-soluble polyetheramine include for example: cellulose acetate/triacetate; polyamide, including aromatic polyamide; polypiperazine; polybenzimidazoline; polyol, including polyphenol; polyacrylonitrile (PAN); polyethersulfone (PES); polysulfone (PS); poly(phthalazinone ether sulfone ketone) (PPESK); poly(vinyl butyral); Polyvinylidene fluoride (PVDF); poly(tetrafluoroethylene) (PTFE); polypropylene (PP); polyethylene (PE) and polyetheretherketone (PEEK).
  • the polymer for making the high permeability membrane is selected from the group consisting of: PS, PES, PVDF, PAN and PE. In a further embodiment, the polymer for making the high permeability membrane is selected from the group consisting of: PS, PES and PVDF. In an additional embodiment, the polymer for making the high permeability membrane is PES.
  • the high permeability membrane is a PES membrane with a polyolefin nonwoven support material.
  • a membrane that may be used in the context of the present invention is a Biomax PB UF membrane as manufactured by Millipore (Billerica, MA). Biomax UF membranes are supplied with MWCO’s ranging from 5 to 1000 kDa (http://wolfson.huii.ac.il/purification/PDF/dialvsis/MILLIPORE UltrafiltrationMemb ranes.pdf and www.millipore.com/oemproducts) and have high permeability (when compared with salt-rejecting membranes, i.e. reverse osmosis or nanofiltration membranes).
  • the high permeability membrane which may be a UF membrane, is manufactured using a method comprising the steps of: a) mixing together a membrane-forming polymer, a water-soluble polyetheramine, and a solvent, said mixture containing no component which reacts chemically with the polyetheramine and b) casting said mixture to form the polymer into a solid membrane.
  • a polyetheramine is a polyether with at least one primary or secondary amine group attached to the polyether backbone, generally at the end of the polymer chain. “Polymer” in this context should be understood to include dimer, turner, and oligomer. Polyetheramines include mono-, di-, tri- or multi-functional primary and secondary amines.
  • the polyether typically contains ethylene oxide and/or propylene oxide monomer units. Many are commercially available, including from suppliers such as Wego Chemical Group (Great Neck, NY, USA), Arpadis Benelux NV (Antwerp, Belgium), Huntsman (The Woodlands, TX, USA) and BASF Intermediates..
  • polyetheramines are water-soluble, and these are preferably used in the embodiment of the invention using a polyetheramine.
  • the solubility of the polyetheramine is at least 0.1% w/v, especially at least 0.2% w/v, at 21°C.
  • the polyetheramine is miscible with water at 21°C.
  • Solubility of polyetheramines in water can be measured using the standard method of Dynamic Light Scattering.
  • DLS detects and monitors the size and number of any particles present when the polyetheramine and water are mixed.
  • One method to determine water solubility using DLS is as follows: Malvern ZetaSizer Nano-S light scattering (DLS) equipment is used to observe formation of particles at a given concentration of polyetheramine in water. Combination of count rate and attenuator monitoring is used to determine the increase in number of particles as the concentration of polyetheramine increases to determine solubility.
  • DLS Malvern ZetaSizer Nano-S light scattering
  • Polystyrene latex is used as the reference material (RI: 1.590; absorption: 0.010 at 633 nm), and water as the dispersant (viscosity: 0.9781 cP; RI: 1.330).
  • the measurements are carried out in Science Brand disposable microcuvettes with a sample volume of 100 pL, at 21°C. Where the polyetheramine and water are not completely miscible, DLS measurements were continued up to the point where visible phase separation was observed.
  • Polyetheramines can be slow to dissolve in water, but solutions of those which are soluble do not phase separate over time on standing once the solution has been formed.
  • Polyetheramines suitable for use in the present invention include those containing two or more ethylene oxide and/or propylene oxide monomer units and at least one, for example 1, 2 or 3, primary or secondary amine units -NHX where X is a hydrogen atom or a Ci-4alkyl group, for example a methyl, ethyl, n-propyl or isopropyl group.
  • the molecular weight of the polyetheramine will of course vary depending on the number of monomer units present. In the second aspect of the invention, and preferably in the first aspect of the invention, the molecular weight is up to 2,500, for example up to 2,000, or up to 1,500, or up to 1,000.
  • the molecular weight will influence the hydrophilicity of the polyetheramine, and polyeramines having a higher content of ethylene oxide or lower content of propylene oxide monomer units will generally be more hydrophilic and therefore water-soluble.
  • the polyetheramine may for example be a mono- or di-amine having the schematic formula:
  • Y-PAO-Y' (I) or a mono-, di- or tri-amine having the schematic formula: in which each of Y, Y' and Y" independently represents an end group at least one of which includes a primary or secondary amine group, and PAO represents a polyalkyleneoxide chain consisting of at least two ethylene oxide and/or propylene oxide monomer units.
  • Suitable amine-containing end groups include: (i) -NHX groups in which X represents a Ci-4alkyl group, for example a methyl group, or, especially, a hydrogen atom, and (ii) Ci-4alkyl groups which may be substituted by an -NHX group or interrupted by an -NH- group.
  • an end group does not contain an amino group, it may for example be a hydrogen atom, a Ci-4alkyl group, an -OH group, or an -OCi- 4alkyl group.
  • the PAO chain may be straight-chain, in which case the polyetheramine may have the schematic formula:
  • a represents the number of propylene oxide (PO) monomer units present and b represents the number of ethylene oxide (EO) monomer units present, it being understood that either a or b can be zero, and that if both PO and EO monomer units are present these may be arranged in random, alternate or block sequence.
  • the PAO chain may be branched, in which case the polyetheramine may have the general formula:
  • R represents a hydrogen atom or a methyl group
  • R represents a hydrogen atom, a methyl or an ethyl group
  • d is 0 or 1
  • c, e and f are the numbers of PO and/or EO monomer units present.
  • polyetheramines include compounds of the following formulae: in which R is H or CH 3 , and x and y are the numbers of EO/PO monomer units in the polyether chain.
  • x is the number of PO monomer units in the poly ether chain.
  • x and z are the number of PO monomer units in two blocks in the polymer chain, and y is the number of EO monomer units in the poly ether chain.
  • x is 2 or 3.
  • x, y and z together represent the total number of PO monomer units present in the branched chain polymer, n is 0 or 1, and R is hydrogen, methyl or ethyl.
  • one or more NH2 end groups can be converted into a secondary amine group, for example:
  • the use of a polyetheramine of the formula (IX) above is preferred.
  • One preferred compound of this type is the compound in which the number of moles of PO is between 5 and 6, giving an approximate molecular weight of 440.
  • the use of a polyetheramine of the formula (VI) is preferred.
  • One preferred compound of this type is the compound in which x in the formula (VI) is on average from 6 to 7, giving an approximate molecular weight of 430.
  • the solvent or mixture of solvents used in the manufacture of a high permeability membrane for use in the context of the present invention will of course depend on the nature of the polymer and any additives present. Generally, the solvent should dissolve the polymer and the additives, and should be miscible with the non solvent (for example water or an alcohol) used in the quench bath. Any of the solvents known for use in membrane casting processes may be used. Suitable solvents include, for example, DMF, NMP, dimethylacetamide, acetone, DMSO and THF. Mixtures of solvents may be used.
  • the casting mixture may contain a non-solvent, of which water is the most common example, although other non-solvents, for example alcohols, for example Ci-4alkanols, or glycol ethers, for example methoxyethanol, ethoxyethanol or propoxyethanol, especially methoxyethanol, may be used.
  • non solvents are generally included to act as viscosity regulators, as viscosity can be important in casting configuration, and may affect speed of precipitation.
  • the casting mixture used to generate a high permeability membrane may contain any additional additives known in the art.
  • So-called “pore forming” additives are typically added to the membrane casting dope in order to increase the porosity and trigger certain membrane morphology.
  • Inorganic additives such as LiCl may be used.
  • hydrophobic polymers or block co-polymers for example polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG) may be added.
  • PVP polyvinylpyrrolidone
  • PEG polyethylene glycol
  • any such additives may be used in the present invention as an alternative to or in addition to the polyetheramine.
  • the casting mixture should not contain components which are reactive with the polyetheramine, if the latter is present. Specifically, the casting mixture should not contain reactive monomers or pre-polymers which will cross-link or otherwise react with the polyetheramine, if it is present.
  • the other components of the casting mixture should not react with the polyetheramine, it is meant that reactions should not take place (or should only take place at a negligible level) at standard temperatures and pressures, e.g. 20°C and atmospheric pressure, during the length of time it takes to prepare the casting mixture and then cast the membrane, e.g. for up to 2, 4 or 6 hours or for up to 1, 2, 4 or 6 days or for up to 1 week.
  • Step (a) of a casting process used to form a high permeability membrane for use in the context of the present invention involves mixing together the membrane-forming polymer, the polyetheramine (if present), the solvent, and any additional components, to form a casting solution, or dope.
  • the dope may be a clear solution, or it can be an emulsion or suspension.
  • the weight ratio of polyetheramine to polymer is an important parameter which determines the pore structure of the finished membrane. It may for example be in the range of from 1:0.1 to 1 :200 w/w, although in another embodiment, the polymer is present in a weight at least equal to that of the polyetheramine.
  • the weight ratio may for example be 1:1 to 1 : 100, for example 1:2 to 1:50, especially 1:5 to 1 :40, w/w.
  • the concentration of polymer in the solvent is suitably in the range of from 1 to 80, for example 4 to 60, for example 8- 35, especially from 12 to 21, %w/w.
  • the concentration of polyetheramine (if present) in the solvent is suitably in the range of from 1 to 90, for example 1 to 5, especially 0.01 to 3, %w/w.
  • Step (b) of a casting process used to form a high permeability membrane for use in the context of the present invention involves casting the mixture of step (a) to form the membrane, and may involve any known casting technique. Casting is the precipitation of the membrane-forming polymer from the mixture of the polymer and additives in the solvent. Phase inversion may be driven by:
  • Step (a) of the casting process may be carried out simultaneously with step (b), but in one embodiment step (a) is carried out as a first step, and once this is completed then step (b) is carried out as a subsequent step.
  • step (b) comprises immersing the mixture produced in step (a) in a medium in which the polymer is insoluble, especially an aqueous medium.
  • the membrane may be cast onto a backing or support, for example a fabric, typically nonwoven polyester or polypropylene, although any form of backing may be used. Casting can be achieved to form membranes in various configurations, for example flat-sheet membranes, made using a doctor blade or a diecoater, involving extrusion of polymer solution through extrusion knives; hollow fibre membranes, where viscous dope is pushed through an extrusion nozzle into quenching solution/solutions on the outside and inside of the fibre; tubular membranes; or FibreplateTM-type membranes. The solvent is generally removed as part of the casting process.
  • any desired post-formation steps may be carried out.
  • the surface of the membrane may be functionalised in any desired way, and various coatings may be applied if desired.
  • the membrane-forming steps described herein result in a high permeability membrane with improved rejection capabilities, specifically exceptionally high water permeability at a given molecular cut off, and reduction of fouling at the surface of the membrane.
  • the described membrane-forming steps allow precise control of the size, number and architecture of membrane pores, thus allowing for the design of membranes for specific applications.
  • a spiral wound membrane element according to the invention having a diameter of between 5 and 7 inches, e.g. about 6.3 or about 6.4 inches, has a PWF of at least 1.8, at least 2, at least 2.5, at least 3 or at least 3.5 gallons per foot square per day per psi (GFD/psi).
  • a spiral wound membrane element according to the invention having a diameter of between 7 and 9 inches, e.g. about 8 inches has a PWF of at least 3, at least 4 or at least 5 gallons per foot square per day per psi (GFD/psi).
  • the spiral wound element having a diameter of between 7 and 9 inches, e.g. about 8 inches comprises a permeate carrier having a thickness of at least 20 mil, e.g. about 20 mil.
  • a method of calculating the PWF of a spiral wound membrane element is provided in Example 5.
  • the spiral wound membrane element comprises at least one feed spacer.
  • the purpose of the feed spacer is to allow the feed solution to flow through the membrane element, with the feed solution becoming more concentrated as it does so.
  • the feed spacer achieves this by providing space for fluid to flow between the membrane surfaces of adjacent membrane envelopes thus allowing for uniform flow of the feed solution between the membrane leaves.
  • the membrane element comprises a plurality of feed spacers.
  • all membrane envelopes are separated from each other by a feed spacer, i.e. there is a feed spacer between each adjacent pair of membrane envelopes, thus allowing feed solution to penetrate between adjacent membrane envelopes.
  • Representative feed spacer materials include polyethylene and polypropylene mesh materials.
  • the thickness of the feed spacer within the spiral wound membrane element may be varied. In one embodiment of the invention, the feed spacer thickness is between 10 and 80 mil. In another embodiment of the invention, the feed spacer thickness is between 15 and 50 mil. In another embodiment of the invention, the feed spacer thickness is between 20 and 50 mil. In another embodiment of the invention, the feed spacer thickness is between 20 and 40 mil. In another embodiment of the invention, the feed spacer thickness is 20, 26, 28, 31, 32, 45 or 46 mil. In another embodiment of the invention, the feed spacer thickness is 20, 31, 32 or 46 mil. In another embodiment of the invention, the feed spacer thickness is 20 or 31 mil.
  • a thicker feed spacer layer may be used.
  • feed spacer materials are manufactured by Conwed Global Netting (Minneapolis, MN 55414, USA).
  • the feed spacer may be deposited (e.g. 3D printed) directly on the membrane (instead of being inserted as a separate sheet within the spiral wound membrane element, i.e. a conventional feed spacer is absent from the element).
  • An example of this type of technology is provided by Aqua Membranes (Albuquerque, NM, USA) using their 3D printed spacers, as described in patent numbers US 2016/0008763 and US 2019/0358590, which are hereby incorporated by reference.
  • a stencil is used to create the feed spacer, for example directly on the active (front) side of the membrane, with the feed spacer material then being cured (hardened) by exposure to UV light.
  • Printing the feed spacer directly on the active (front) side of the membrane allows the use of thinner feed spacers (e.g. as thin as 10 mil), thus allowing more space for other components of the spiral wound membrane element, leading to an overall increase in membrane surface area.
  • the spiral wound membrane element has a permeate flux of at least 0.7 GFD/psi, as measured using a 4% w/v Whey Protein Concentrate 80 (WPC80) solution.
  • the inlet feed pressure of the spiral wound membrane element is less than 100 psi, is less than 80 psi, is less than 50 psi or is less than 40 psi, for example about 30 psi.
  • Such inlet pressures are particularly useful in the context of an element comprising an ultrafiltration membrane.
  • the difference between the inlet pressure and the outlet pressure of the spiral wound membrane element i.e. the pressure drop across the element
  • the difference between the inlet pressure and the outlet pressure of the spiral wound membrane element is less than 50 psi, is less than 40 psi, is less than 30 psi, is less than 20 psi, is less than 15 psi or is less than 10 psi.
  • the difference between the inlet pressure and the outlet pressure of the spiral wound membrane element is about 15 psi.
  • the membrane envelope comprises only a single sealed permeate flow compartment.
  • this means that the membrane envelope is not sub-divided into separate sealed permeate flow compartments (e.g. with a sealant line extending radially from the proximal edge region 4a of the membrane envelope towards the distal sealant line 12, with reference to Figures 3 and 4), wherein once permeate has entered a particular sealed permeate flow compartment, it cannot pass into a different sealed permeate flow compartment.
  • the spiral wound membrane element comprises a permeate collector which is a tube comprising perforations which allow permeate exiting the permeate carrier to access the interior of the permeate tube.
  • the diameter of the perforations is between 2/16 and 8/16 of an inch or between 3/16 and 8/16 of an inch, e.g. about 4/16 or 1 ⁇ 4 (one quarter) of an inch.
  • the perforations form at least 1.17% of the surface area of the permeate collector, e.g between 1.17% and 6%, between 1.2% and 5% or between 2% and 5% of the surface area of the permeate collector.
  • the feed solution (as input into the spiral wound membrane element) has a viscosity which is less than the viscosity of a 15% w/v Whey Protein Concentrate 80 (WPC80) solution.
  • the viscosity of the feed solution may be compared to the viscosity of a comparative 15% w/v Whey Protein Concentrate 80 (WPC80) solution by methods that are well-known in the art.
  • the feed solution has a viscosity which is equal to or less than the viscosity of a 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5% or 4% w/v Whey Protein Concentrate 80 (WPC80) solution.
  • the viscosity of the feed solution falls within a range which is bounded by minimum and maximum viscosities represented by the viscosity of pure water and a 10% w/v Whey Protein Concentrate 80 (WPC80) solution respectively.
  • the viscosity of the feed solution is approximately equivalent to the viscosity of a 4 % w/v Whey Protein Concentrate 80 (WPC80) solution.
  • References to “solution” herein are understood to apply equally to suspensions or colloids.
  • the dynamic viscosity of the feed fluid is within the range 1 centipoise (cP) / 1 millipascal-second (mPa s), which is the dynamic viscosity of pure water, to 1000 cP / mPa s, when measured at 20 °C and neutral pH.
  • the dynamic viscosity of the feed fluid is within the range 1 to 800, 1 to 600, 1 to 500, 1 to 400, 1 to 300, 1 to 200, 1 to 100, 1 to 50, 1 to 40, 1 to 30, 1 to 20 or 1 to 10 cP / mPa s, when measured at 20 °C and neutral pH.
  • the spiral wound membrane element has a permeate flux of at least 0.8 GFD/psi or at least 0.9 GFD/psi, as measured using a 4% w/v Whey Protein Concentrate 80 (WPC80) solution.
  • the spiral wound membrane element has a diameter of between 4 and 7 inches and an output of at least 165 GD/psi, as measured using a 4% w/v Whey Protein Concentrate 80 (WPC80) solution.
  • the spiral wound membrane element has a diameter of between 3 and 4 inches and an output of at least 50 GD/psi, as measured using a 4% w/v Whey Protein Concentrate 80 (WPC80) solution.
  • the spiral wound membrane element has a diameter of between 7 and 9 inches and an output of at least 270 GD/psi, as measured using a 4% w/v Whey Protein Concentrate 80 (WPC80) solution.
  • WPC80 Whey Protein Concentrate 80
  • the spiral wound membrane elements of the present invention may be utilized in many applications including water pre-treatment prior to desalination, desalination, nanofiltration (NF), ultrafiltration (UF), microfiltration (MF), brackish water desalination, wastewater treatment, contamination removal, bacterial and virus removal as well as separation of proteins and other active or inactive macromolecules in dairy, food and beverage and biotech applications.
  • Particular applications include protein filtration, protein purification, protein concentration, enzyme filtration, enzyme purification, enzyme concentration, pharmaceutical biomolecule (e.g.
  • the protein is a milk-derived protein, such as casein or whey.
  • the present invention comprises methods of using the spiral wound membrane elements described herein in such applications, as well as systems useful in such applications comprising a spiral wound membrane element of the present invention.
  • the spiral wound membrane elements of the invention may also be used in a method of diafiltration.
  • Diafiltration is a technique that uses a membrane to completely remove, replace, or lower the concentration of salts or solvents from solutions containing proteins, peptides, nucleic acids, and other biomolecules.
  • the process selectively utilizes a permeable (porous) membrane filter to separate the components of solutions and suspensions based on their molecular size.
  • a permeable membrane filter In the case of a UF membrane, the membrane retains molecules that are larger than the pores of the membrane while smaller molecules such as salts, solvents and water, which are 100% permeable, freely pass through the membrane.
  • the solution retained by the membrane is known as the concentrate or retentate.
  • the solution that passes through the membrane is known as the filtrate or permeate.
  • a membrane for concentration is selected based on its rejection characteristics for the sample to be concentrated.
  • the molecular weight cut-off (MWCO) of the membrane should be 1/3 rd to l/6th the molecular weight of the molecule to be retained (3-6X Rule). This is to assure complete retention.
  • a sample to be concentrated/diafiltered is fed into a spiral wound membrane element of the present invention containing a suitable membrane (e.g. a UF membrane) that will retain the large molecules.
  • a suitable membrane e.g. a UF membrane
  • the salt molecule to volume ratio in the concentrate remains constant so the ionic strength of the concentrated solution remains relatively constant.
  • the ionic strength of the concentrate (retentate) solution can subsequently be reduced by “washing” the remaining salt out with water, a process called diafiltration. This is essentially a dilution process and is performed in conjunction with a concentration process. Water is added while filtrate is removed. If the washing solution is another buffer instead of water, the new buffer salt will replace the initial salt in the sample.
  • Diafiltration also called membrane filtration in dilution mode
  • Diafiltration may be performed either in batch (discontinuous) or continuous processing mode.
  • diluant is added to and permeate is withdrawn from the system.
  • the fundamental difference between the two configurations is that in batch operation, the retentate stream is recycled into the feed tank where it is mixed with the content of the reservoir and with fresh diluant.
  • the concentration of membrane-permeable microsolutes in the feed tank decreases over time, and the final product is obtained directly in the feed reservoir when operation is terminated.
  • continuous processing is performed in a flow-through manner with both permeate and retentate are continuously added and removed.
  • Diafiltration is an operation mode of a pressure-driven membrane filtration process in which a diluent (i.e. water or any other solvent or buffer) is added to the process feed in order to enhance the degree of separation of membrane-retained macrosolutes from membrane-permeable microsolutes.
  • a diluent i.e. water or any other solvent or buffer
  • diafiltration may be performed with microfiltration, ultrafiltration, nanofiltration, or reverse osmosis membranes.
  • the separation target can be reached by using either batch or continuous processing mode.
  • Diafiltration is an indispensable tool in separating multicomponent process streams and is widely used in the food and beverage, chemical, biotechnological, and pharmaceutical industries.
  • the invention comprises a method of diafiltration of a macromolecule using a spiral wound membrane element as described herein.
  • the invention also comprises a macromolecule diafiltration system comprising a spiral wound membrane element as described herein.
  • the macromolecule may be, for example, a protein.
  • the invention comprises a method of concentration/diafiltration of a macromolecule using a spiral wound membrane element as described herein.
  • the invention also comprises a macromolecule concentration/diafiltration system comprising a spiral wound membrane element as described herein.
  • the macromolecule may be, for example, a protein.
  • the invention comprises a method of manufacturing a spiral wound membrane element as described herein comprising the steps of: a. assembling a membrane envelope comprising a solid high permeability membrane and a permeate carrier; b. attaching a plurality of said membrane envelopes to a permeate collector such that the permeate carriers are in fluid communication with the permeate collector and wherein; and c. winding the membrane envelopes around to the permeate collector to form the spiral wound element.
  • the high permeability membrane is formed via the steps of: a. mixing together a membrane-forming polymer, a water-soluble polyetheramine, and a solvent, said mixture containing no component which reacts chemically with the polyetheramine; and b. casting said mixture to form the polymer into a solid membrane.
  • one embodiment of the invention comprises a method of manufacturing a spiral wound membrane element as described herein comprising the steps of: a. mixing together a membrane-forming polymer, a water-soluble polyetheramine, and a solvent, said mixture containing no component which reacts chemically with the polyetheramine; b. casting said mixture to form the polymer into a solid high permeability membrane; c. assembling a membrane envelope comprising said solid high permeability membrane and a permeate carrier; d. attaching a plurality of said membrane envelopes to a permeate collector such that the permeate carriers are in fluid communication with the permeate collector; and e. winding the membrane envelopes around to the permeate collector to form the spiral wound element.
  • the invention comprises a method of manufacturing a spiral wound membrane element; the method comprising: modifying an original spiral wound membrane element design in order to reduce hydraulic restriction on the permeate side of said spiral wound membrane element by: (i) reducing the length of the membrane envelope whilst ensuring that the membrane surface area available for filtration remains essentially the same or increases, by increasing the number of membrane envelopes within said spiral wound membrane element; and/or (ii) increasing the thickness of the permeate carrier; to produce a new spiral wound element design; wherein the spiral wound membrane element comprises a permeate collector to which are attached a plurality of membrane envelopes; wherein the membrane envelopes comprise a membrane and a permeate carrier; wherein the permeate carrier is in fluid communication with the permeate collector; and making a spiral wound membrane element according to the new spiral wound membrane element design.
  • the membrane may be a high permeability membrane as described herein.
  • the method comprises reducing the length of the membrane envelope, whilst ensuring that the membrane surface area available for filtration remains essentially the same by increasing the total number of membrane envelopes within said spiral wound membrane element; and increasing the thickness of the permeate carrier.
  • a spiral wound membrane element according to an embodiment of the invention may be manufactured according to the following steps.
  • a permeate carrier stack is created by stacking permeate carrier pre-cut to the appropriate size onto a permeate carrier leader, which is longer than the subsequent sheets.
  • the permeate carrier leader is then attached to the permeate tube and wrapped onto it.
  • the permeate carrier stack of the appropriate number of sheets (corresponding to the number of membrane leaves required) is added on the leader.
  • the appropriate number of membrane sheets (corresponding to the number of membrane leaves required) are pre-cut and folded in half (face to face) onto pre-cut sheets of feed spacers.
  • the membrane sheets are bonded using polyurethane adhesive (back to back) through permeate carrier sheets to form membrane leaves and adhered to the permeate tube creating a seal.
  • the permeate tube is then rotated and the spiral is formed. Once the adhesive has been cured, the membrane element is trimmed and caged.
  • Example 2 Improved Permeate Flow as Demonstrated by Improved Flux Under An
  • the configuration of the spiral wound membrane elements of the present invention results in an improved permeate flow. This may be illustrated by measuring the flux through the element under conditions of intended use, for example measurement of the flow of permeate during Whey Protein Concentrate (WPC) solution filtration using the element.
  • WPC Whey Protein Concentrate
  • a typical protocol for measuring the flux of permeate during concentration or recirculation of a WPC solution through a spiral wound membrane element is briefly described as follows.
  • a 4% w/v solution of Whey Protein Powder Concentrate 80 (WPC80) is prepared using ultra-filtered water (the concentration of whey protein in such a solution corresponds to the concentration of whey protein in a WPC40 solution as processed during commercial whey protein concentrate production).
  • WPC80 Whey Protein Powder Concentrate 80
  • Figure 1 A shows the permeate flux values as measured in liters per minute
  • figure IB shows the permeate flux values as measured in GFD/psi
  • figure 1C shows total processed volume in liters of a spiral wound membrane element containing 18 membrane envelopes (or leaves) prepared according to Example 1 (“Gen 2 AB”)
  • the two comparator spiral wound membrane elements are a 10K UF 6438/31 Sanitary Element, ST2B6438 (Synder Filtration, Vacaville, CA, USA) (“Synder”), and an element manufactured by Applied Biomimetic (“Gen 1 AB”). Further details of the configurations of the elements studied are shown in the table below:
  • Permeate was collected for 30 seconds at various intervals after starting the analysis (the whole run lasting 24 hours, thus mimicking a production cycle) and weighed to calculate the element output in liters per minute at each time point.
  • the output of a membrane element according to an embodiment of the present invention containing 18 membrane envelopes is vastly superior to the membrane element containing 12 membrane envelopes, with permeate flux approximately 40% greater in the membrane element according to the present invention than the comparator membrane elements.
  • the elements comprised permeate carriers with thicknesses of 10 mil (Guilford Performance Textiles, Wilmington, NC) and 12 mil (Guilford Performance Textiles, Wilmington, NC and Hornwood, Inc. (Lilesville, NC)).
  • thicknesses 10 mil (Guilford Performance Textiles, Wilmington, NC) and 12 mil (Guilford Performance Textiles, Wilmington, NC and Hornwood, Inc. (Lilesville, NC)).
  • increasing the number of membrane envelopes and reducing the length of the membrane envelopes increases the permeate flow as measured in GFD/PSI and the output as measured in kg/min.
  • Example 4 Output of various spiral wound membrane elements
  • the configuration of various spiral wound membrane elements and their output as measured in gallons per day per pound per square inch (GD/psi) are listed in the following Table 2 (as measured by a WPC flux test as described in Example 2).
  • Example 5 Output of various spiral wound membrane elements as measured by pure water flux
  • a PWF test was carried as described in the following text. When carrying out a PWF test, it is important that the element(s) to be tested are not allowed to dry out. Elements should be stored in a sealed bag or (between tests) in a vat of water. Pre filtered water should be used for element flushing and testing. An Infrared (IR) thermometer should be used to measure the water temperature in the tank whenever needed.
  • IR Infrared
  • Inlet and outlet pressures iv.
  • g. Record the following i. The tank temperature (after testing) ii. Collection time (seconds) h. Weigh the permeate and record weight in Kg
  • step 4 Repeat step 4. a. If the permeate weight from step 4 and step 5 are not within 5% of each other, repeat step 4 again.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Water Supply & Treatment (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)

Abstract

Un élément de membrane enroulé en spirale comprend un collecteur de perméat sur lequel est montée une pluralité d'enveloppes de membrane ; les enveloppes de membrane comprenant une membrane et un support de perméat ; le support de perméat étant en communication fluidique avec le collecteur de perméat et la longueur de l'enveloppe de membrane étant inférieure à 35 pouces. Les éléments de membrane enroulés en spirale de l'invention présentent un flux de fluide amélioré.
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160008763A1 (en) 2013-02-28 2016-01-14 Aqua Membranes Llc Improved Spiral Wound Element Construction
KR20170042560A (ko) * 2014-08-19 2017-04-19 쿠리타 고교 가부시키가이샤 역침투막 장치 및 그 운전 방법
WO2017085322A1 (fr) 2015-11-20 2017-05-26 Applied Biomimetic A/S Procédé de préparation de membranes
US20190358590A1 (en) 2016-09-20 2019-11-28 Aqua Membranes Inc. Permeate flow paterns

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Publication number Priority date Publication date Assignee Title
US20160008763A1 (en) 2013-02-28 2016-01-14 Aqua Membranes Llc Improved Spiral Wound Element Construction
KR20170042560A (ko) * 2014-08-19 2017-04-19 쿠리타 고교 가부시키가이샤 역침투막 장치 및 그 운전 방법
WO2017085322A1 (fr) 2015-11-20 2017-05-26 Applied Biomimetic A/S Procédé de préparation de membranes
US20180345226A1 (en) * 2015-11-20 2018-12-06 Applied Biomimetic A/S Method of preparing membranes
US20190358590A1 (en) 2016-09-20 2019-11-28 Aqua Membranes Inc. Permeate flow paterns

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