SPACER FOR A SPIRAL WOUND MEMBRANE

Abstract

A component for a spiral wound membrane, suitably for water filtration. The component includes an integrally formed non-uniform lattice structure. The lattice structure includes a first and second repeating unit cell, wherein the first and second unit cell are different.

Claims

1. A component for a spiral membrane, such as for water filtration, comprising an integrally formed non-uniform lattice structure, wherein the lattice structure comprises a first and second repeating unit cell, wherein the first and second unit cells are different.

2. The component for a spiral membrane according to claim 1, wherein the component is a permeate carrier, a backing layer or a combined permeate-backing layer.

3. (canceled)

4. (canceled)

5. (canceled)

6. (canceled)

7. The component according to claim 1, wherein the pore size of the first and/or second unit cell, when present, of the lattice structure is ?10 ?m and/or is ?5 mm.

8. (canceled)

9. The component according to claim 1, wherein the pore size of the first and/or second unit cell, when present, of the lattice structure is ?40 ?m and/or is ?1 mm.

10. (canceled)

11. The component according to claim 1, wherein the second repeating unit cell has a different strut thickness compared to the first repeating unit cell.

12. The component according to claim 1, wherein the average strut thickness of the first and/or second unit cell, when present, of the lattice structure is ?10 ?m and/or is ?5 mm.

13. (canceled)

14. The component according to claim 1, wherein the average strut thickness of the first and/or second unit cell, when present, of the lattice structure is ?40 ?m and/or is ?1 mm.

15. (canceled)

16. (canceled)

17. (canceled)

18. The component according to claim 1, wherein the lattice structure comprises a higher archival lattice structure.

19. (canceled)

20. The component according to claim 1, wherein a Reynolds number (Re) of at least 2300 is obtainable at a flow rate of between 0 and 1 m/s.

21. The component according to claim 1, wherein the component is operable to function at a transmembrane pressure of 30 bar to 50 bar or 3 bar to 15 bar.

22. (canceled)

23. The component according to claim 1, wherein the component has a packing density of ?650 m.sup.2/m.sup.3.

24. (canceled)

25. (canceled)

26. The component according to claim 1, wherein a unit cell comprises the scalar fields of two or more unit cells mixed to produce a new mixed unit cell.

27. The component according to claim 1, wherein a unit cell is shelled to form an internally hollow structure.

28. A membrane envelope comprising: a. a permeate carrier or permeate-backing layer component according to claim 2; and b. a filtration membrane layer, wherein the filtration membrane layer comprises an active layer and a support layer, wherein the active layer comprises graphene or a derivative thereof, a transition metal dichalcogenide (TMD) and/or a metal-organic framework.

29. (canceled)

30. (canceled)

31. The membrane envelope according to any of claim 28, wherein a first side of the component is adjacent to the backing layer or support layer of the first filtration membrane layer and a second side of the component is adjacent to the backing layer or support layer of the second filtration membrane layer, wherein the first and second filtration membrane layers may be parts of the same folded membrane or two parts from discrete membranes.

32. The membrane envelope according to claim 28, wherein the permeate-backing layer component comprises ?40% of the total membrane envelope thickness.

33. (canceled)

34. (canceled)

35. (canceled)

36. (canceled)

37. (canceled)

38. A method of preparing a component according to claim 1, the method comprising the steps of: a. producing the component by additive manufacturing the lattice structure, wherein the wherein the additive manufacturing method is stereolithography, digital light processing, two-photon polymerisation, two colour photo-polymerisation, inkjet printing, binder jet printing, stereolithography (SLA), direct ink writing, three-dimensional printing, selective laser sintering, selective laser melting, laminated object manufacturing, and/or fused deposition modelling.

39. (canceled)

40. (canceled)

Description

BRIEF DESCRIPTION OF DRAWINGS

[0267] Aspects of the present disclosure will now be described hereinafter, by way of example only, with reference to the acompanying drawings in which:

[0268] FIG. 1 shows a cross sectional view of a polyamide thin film composite (TFC) reverse osmosis (RO) industrial desalination membrane. The membrane (100) comprises 3 layers: (i) an active layer (102); (ii) a supporting layer (104); and (iii) a backing layer (106).

[0269] FIG. 2 shows a perspective view of an additive printed component (200) operable as a permeate carrier to allow permeate to flow.

[0270] FIG. 3 shows a perspective view of an additive printed component (300) operable as a backing layer to allow permeate to flow.

[0271] FIG. 4 shows a perspective view of an additive printed component (400) operable as a combined permeate carrier and backing layer to allow permeate to flow.

EXAMPLES

Permeate Carrier Component

[0272] Comparative Example 1: Referring to FIG. 1, a polyamide TFC RO industrial desalination membrane formed of: a feed spacer having knitted structure and thickness of 863 ?m; and membrane envelopes comprising a permeate carrier having knitted irregular non-lattice structure and thickness of 457 ?m; and a membrane (100) comprising 3 layers: (i) an active layer (102) made from interfacial polymerisation of polyamide having a thickness of 100 nm; (ii) a supporting layer (104) made from UF PES having thickness of 50 ?m; and (iii) a backing layer (106) made from a nonwoven polyester having a thickness of 120 ?m. The membrane had packing density of 1000 m.sup.2/m.sup.3. A seawater feed after pre-treatment with a salt concentration of 20,000 ppm, was directed into the membrane. A flow velocity of 1.2 m/s, at pressure of 55 bar was required to generate a Re number higher than 2300 and obtain a permeate flux of 2 L/(m.sup.2 hr).

[0273] Example 1: Referring to FIG. 2, a polyamide TFC RO industrial desalination membrane formed of: a feed spacer having knitted structure and thickness of 863 ?m; and membrane envelopes comprising a permeate carrier component (200) according to the present invention having a non-uniform lattice structure and thickness of 275 ?m; and a membrane comprising 3 layers: (i) an active layer made from interfacial polymerisation of polyamide having a thickness of 100 nm; (ii) a supporting layer made from UF PES having thickness of 50 ?m; and (iii) a backing layer made from nonwoven polyester having a thickness of 120 ?m.

[0274] The permeate carrier (200) is formed of a lattice structure that is non-uniform such that the pore size of the unit cell size changes along the Z plane of the lattice structure. The unit cell pore size is largest in the middle (202) of the lattice structure and the unit cell pore size decreases toward the top (204a) and bottom (204b) faces of the lattice structure.

[0275] A seawater feed after pre-treatment with a salt concentration of 20,000 ppm, was directed into the polyamide TFC RO industrial desalination membrane comprising the permeate carrier component (200). The membrane was able to operate at a flow velocity between 0 and 1 m/s to achieve a Re number of 2300. At a seawater feed flow velocity of 1 m/s, a pressure of 45 bar generated a Re number higher than 2300 and obtained a permeate flux rate of 3 L/(m.sup.2 hr). The structure of the component (200) resulted in an increase in packing density by 15% from the comparative examples, with a packing density of 1000 m.sup.2/m.sup.3 to 1150 m.sup.2/m.sup.3.

Backing Layer Component

[0276] Comparative Example 2: A spiral wound membrane formed of: a feed spacer having knitted structure and thickness of 863 ?m; and membrane envelopes comprising a permeate carrier having knitted irregular non-lattice structure and thickness of 457 ?m; and a membrane comprising 3 layers: (i) an active layer made from interfacial polymerisation of polyamide having thickness of 150 nm; (ii) a supporting layer made from UF PES having thickness of 80 ?m; and (iii) a backing layer made from nonwoven polyester having thickness of 150 ?m. The spiral wound membrane had a packing density of 900 m.sup.2/m.sup.3. A transmembrane pressure of 7 bar, using a brackish water feed of 2000 ppm MgSO4, was required to achieve a water yield of 30 to 50 L/(m.sup.2 hr).

[0277] Example 2: Referring to FIG. 3, a spiral wound membrane formed of: a feed spacer having knitted structure and thickness of 863 ?m; and membrane envelopes comprising a permeate carrier having knitted irregular non-lattice structure and thickness of 457 ?m, and a membrane comprising 3 layers: (i) an active layer made from interfacial polymerisation of polyamide having thickness of 150 nm; (ii) a supporting layer (104) made from UF PES having thickness of 80 ?m; and (iii) a backing layer component according to the present invention (300), having a thickness of 90 ?m.

[0278] The backing layer (300) is formed of a lattice structure that is non-uniform such that the pore size of the unit cell size changes along the Z plane of the lattice structure. The unit cell pore size is largest from the bottom face to the middle (302) of the lattice structure and the unit cell pore size decreases toward the top face (304) of the lattice structure.

[0279] The use of backing layer component (300), resulted in an increase in packing density by 5% from comparative example 2, with a packing density of 1000 m.sup.2/m.sup.3, to 1050 m.sup.2/m.sup.3. A transmembrane pressure of 5 bar, using a brackish water feed of 2000 ppm MgSO4, generated a water yield of 30 to 50 L/(m.sup.2 hr).

Combined Permeate Carrier and Backing Layer Component

[0280] Comparative Example 3: An 8-inch industrial spiral wound unit from Toray comprising: a feed spacer having thickness of 660 ?m; membrane envelopes comprising a permeate carrier having a thickness of 457 ?m and an irregular non-lattice; and a Toray membrane comprising: (i) an active separation layer of crosslinked aromatic polyamide with thickness of 200 nm; (ii) a supporting layer (104) of PES having thickness of 45 ?m; and (iii) a backing layer (106) made from nonwoven polyester having thickness of 100 ?m and an irregular non-lattice structure. The membrane is spiral wound into the spiral wound unit, together with the traditional knitted feed spacer. The spiral wound unit has a packing density of ?1000 m.sup.2/m.sup.3.

[0281] Example 3: Referring to FIG. 4, there is provided a spiral wound unit comprising: a feed spacer having thickness of 660 ?m; and membrane envelopes comprising a membrane comprising: (i) an active layer of crosslinked aromatic polyamide with a thickness of 200 nm; (ii) a supporting layer of PES having thickness of 45 ?m; and (iii) a combined permeate carrier and backing layer component having a non-uniform lattice structure according to the present invention (400), with an overall thickness of 120 ?m (406). The membrane envelopes were spiral wound into a spiral wound unit, together with the traditional knitted feed spacer.

[0282] The combined permeate carrier and backing layer component (400) is formed of a lattice structure that is non-uniform such that the pore size of the unit cell size changes along the Z plane of the lattice structure. The unit cell pore size is largest from the top face to the middle (402) of the lattice structure and the unit cell pore size decreases toward the bottom face (404) of the lattice structure.

[0283] The packing density of the spiral wound unit containing the membrane according to the present invention increased by 50% compared to comparative example 3 with a packing density of 1000 m.sup.2/m.sup.3 to 1500 m.sup.2/m.sup.3. A transmembrane pressure of 39 bar, when using a seawater feed, was required to obtain a permeate flux of 2 L/(m.sup.2 hr).

[0284] All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

[0285] Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0286] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.