Membrane-assisted fluid separation apparatus and method

• US 20040211726A1
• Filed: 06/14/2004
• Published: 10/28/2004
• Est. Priority Date: 06/22/2001
• Status: Active Grant

• Current Assignee: Petro SEP Corporation
• Original Assignee: Petro Sep International, Ltd.
• Inventors: Kazi, Abdul M., Baig, Fakhir U., Al-Hassani, Aiser
• Granted Patent: US 7,459,084 B2
• Time in Patent Office: Days
• US Class Current: 210/640
• CPC Class Codes: B01D 2313/20 Specific housing
• CPC Class Codes: B01D 2313/203 Open housings
• CPC Class Codes: B01D 2313/22 Cooling or heating elements
• CPC Class Codes: B01D 2313/221 Heat exchangers
• CPC Class Codes: B01D 53/22 by diffusion manufacturing semi-permeable membranes B01D67/00; form, structure or properties of semi-permeable membranes B01D69/00; material for semi-permeable membranes B01D71/00
• CPC Class Codes: B01D 61/36 Pervaporation; Membrane distillation; Liquid permeation
• CPC Class Codes: B01D 61/3631 comprising multiple vapour permeation steps
• CPC Class Codes: B01D 63/02 Hollow fibre modules
• CPC Class Codes: B01D 63/031 Two or more types of hollow fibres within one bundle or within one potting or tube-sheet
• CPC Class Codes: B01D 63/043 with separate tube sheets
• CPC Class Codes: C02F 1/041 by means of vapour compression
• CPC Class Codes: C02F 1/44 by dialysis, osmosis or reverse osmosis general membrane separation processes B01D61/00, membrane modules B01D63/00, electrodialysis C02F1/4693, combination of membrane modules and bioreactors C02F3/1268
• CPC Class Codes: C02F 1/447 by membrane distillation distillation and evaporation without the use of membranes C02F1/04
• CPC Class Codes: C02F 1/448 by pervaporation
• CPC Class Codes: C02F 2103/08 Seawater, e.g. for desalination
• CPC Class Codes: Y02A 20/124 Water desalination
• CPC Class Codes: Y02A 20/131 Reverse-osmosis

Abstract

This present invention relates to a fluid separation module adapted to separate a given fluid mixture into permeate and retentate portions using bundles of hollow fiber membranes. The membranes may be composed of different kinds of membranes depending on the application being used to separate the fluid mixture. The fluid separation module may be used to separate fluid mixtures by a number of different processes, including but not limited to, pervaporation, vapour permeation, membrane distillation (both vacuum membrane distillation and direct contact membrane distillation), ultra filtration, microfiltration, nanofiltration, reverse osmosis, membrane stripping and gas separation. The present invention also provides an internal heat recovery process applied in association with those fluid separation applications where separation takes place by evaporation through the membrane of a large portion of the feed into permeate. Desalination and contaminated water purification by means of vacuum membrane distillation are just two examples where the internal heat recovery process may be applied. In these two examples, large portions of the feed are separated by membranes into a high purity water permeate stream by evaporation through the membranes and into a retentate stream containing a higher concentration of dissolved components than present in the feed. In this process the permeate vapour that is extracted from the fluid separation module is compressed by an external compressor to increase the temperature of the vapour higher than the temperature of the feed entering the separation module. Heat from the permeate vapour at the elevated temperature is transferred back to the incoming feed fluid mixture entering the fluid separation module in a condenser/heat exchange.

Claims

1. A fluid separation apparatus comprising:

a. a hollow housing defining a separation chamber, having at least one permeate outlet to permit one or more permeate components of the feed fluid mixture to exit the housing;

b. at least one feed inlet for feeding a fluid mixture into the housing;

c. at least one bundle of hollow fiber membranes contained within the housing having first and second open ends, the first ends being in fluid communication with a feed inlet; and

d. at least one retentate outlet to permit one or more non-permeate components of the feed fluid mixture to exit the fluid separation module;

whereby the feed fluid mixture passes through the hollow fiber membranes such that the one or more permeate components of the feed fluid mixture migrate across the walls of the membranes to a permeate region defined between the fiber membranes and an interior wall of the housing, and the one or more retentate portions of the feed fluid mixture pass along the length of the membranes to the retentate outlet.

2. The apparatus of claim 1 wherein the ends of a bundle of hollow fiber membranes are each secured by a holding member comprising a tube sheet, such that the ends of the hollow fiber membranes are exposed to the feed inlet and retentate outlet, respectively.

3. The apparatus of claim 1 wherein the housing has two open ends which are sealed by first and second sealing members respectively, each sealing member comprising openings through which the ends of the bundle of membranes is inserted, whereby the ends of the hollow fiber membranes are exposed to a region external to each sealing member.

4. The apparatus of claim 3 wherein each end of the bundle of membranes is secured by a holding member having a threaded portion, and the bundle is secured to each sealing member by threaded members engaging the threaded portions of the holding members.

5. The apparatus of claim 3 wherein one end of the bundle of membranes is secured to a holding member by threaded members engaging threaded portions of the holding member, and the opposite end of the bundle of membranes is secured to the sealing member in a fluid-tight slip fit engagement.

6. The apparatus of claim 1 wherein the housing has one open end sealed by means of a sealing member containing at least one opening through which a feed inlet passes whereby the feed inlet connects to the ends of at least one bundle of membranes by means of a connecting member, and said sealing member contains at least one opening through which a retentate outlet passes, whereby the retentate outlet connects to the ends of at least one bundle of membranes.

7. The apparatus of claim 2 wherein the bundle of hollow fiber membranes is supported along its length by one or more rods.

8. The apparatus of claim 7 wherein the rod bundle of hollow fiber membranes is supported along its length by at least two telescoping rods, each rod comprising two or more rod portions interlocking in sliding relation.

9. The apparatus of claim 8 wherein each rod consists of at least three rod portions, comprising two end rods each having one end fixed into the medial surface of a holding member and a medial rod, whereby opposite ends of the medial rod engage the two end rods in a telescoping relation.

10. The apparatus of claims 2 wherein the bundle of hollow fiber membranes is enclosed in a sleeve that has openings, the sleeve protecting the physical integrity of the hollow fiber membranes contained within said sleeve but allowing the passage of fluids through the sleeve.

11. The apparatus of claim 10 wherein the sleeve consists of two or more elements that move telescopically in relation to one another.

12. The apparatus of claim 6, wherein the two or more bundles of membranes are connected to one another in series.

13. The apparatus of claim 6, wherein the two or more bundles of membranes are connected to one another in parallel.

14. The apparatus of claim 6 wherein two or more bundles of membranes are physically supported by a bearing means against the interior of the housing.

15. The apparatus of claim 2 wherein a first endcap is secured to an inlet end of the housing such that a feed inlet region is defined between the first endcap and the first sealing member.

16. The apparatus of claim 15 wherein a second endcap is secured to an outlet end of the housing such that a retentate outlet region is defined between the second endcap and the second sealing member.

17. The apparatus of claim 16 wherein the first endcap comprises a feed inlet.

18. The apparatus of claim 17 wherein retentate exits the fiber membranes into the retentate outlet region.

19. The apparatus of claim 18 wherein the second endcap comprises a retentate outlet.

20. The apparatus of claim 6 wherein one or more endcaps is secured to the end of the housing such that a feed inlet region is defined between said endcap and the sealing member, and a retentate outlet region is defined between said endcap and the sealing member, and the feed inlet region and retentate outlet region are physically separate from one another.

21. The apparatus of claim 20, wherein the endcap creating the feed inlet region has at least one opening through which a feed inlet passes and empties feed into said feed inlet region.

22. The apparatus of claim 21, wherein the endcap creating the retentate outlet region has at least one opening through which a retentate outlet passes and permits retentate within the retentate outlet region to exit the housing.

23. The apparatus of claim 1 wherein permeate traverses the walls of the hollow fiber membranes by means of pervaporation, vapour permeation, membrane distillation including vacuum membrane distillation, direct contact membrane distillation, ultra filtration, microfiltration nanofiltration, reverse osmosis, membrane stripping, gas separation or a combination thereof.

24. The apparatus of claim 16 wherein a first heating area is defined between the first endcap and the first sealing member and a second heating area is defined between the second endcap and the second sealing member, the first and second heating areas each providing at least one heating fluid inlet and at least one heating fluid outlet to allow the passage of heated fluid therethrough.

25. The apparatus of claim 15 wherein the feed inlet passes through the first endcap and supplies feed fluid mixture directly to the end of at the bundle of hollow fiber membranes in fluid-tight relation.

26. The apparatus of claim 25 wherein the ends of the bundles of hollow fiber membranes are interconnected in fluid-tight communication by conduits to create a series of serially connected bundles of hollow fiber membranes through which the feed fluid mixture is conveyed to the retentate outlet.

27. The apparatus of claim 26 wherein the conduits are disposed within in the first and second heating areas.

28. The apparatus of claim 27 wherein the feed fluid mixture is heated within the conduits by heated fluid passing over said conduits within the first and second heating areas.

29. The apparatus of claim 28 wherein the feed fluid mixture is separated into permeate and retentate portions by means of pervaporation, vapour permeation, membrane distillation including vacuum membrane distillation, direct contact membrane distillation, ultra filtration, microfiltration nanofiltration, reverse osmosis, membrane stripping, gas separation or a combination thereof.

30. The apparatus of claim 26 wherein the feed inlet passes through the first endcap and supplies feed fluid mixture directly to the end of at the bundle of hollow fiber membranes in fluid-tight relation.

31. The apparatus of claim 30 wherein the ends of the bundles of hollow fiber membranes are interconnected in fluid-tight communication by conduits to create a series of serially connected bundles of hollow fiber membranes through which the feed fluid mixture is conveyed to the retentate outlet.

32. The apparatus of claim 31 wherein the conduits are disposed within in the first and second heating areas.

33. The apparatus of claim 32 wherein the feed fluid mixture is heated within the conduits by heated fluid passing over said conduits within the first and second heating areas.

34. The apparatus of claim 26 wherein the feed fluid mixture is separated into permeate and retentate portions by means of pervaporation, vapour permeation, membrane distillation including vacuum membrane distillation, direct contact membrane distillation, ultra filtration, microfiltration nanofiltration, reverse osmosis, membrane stripping, gas separation or a combination thereof.

35. The apparatus of claim 1 for use in the process of desalination.

36. The apparatus of claim 35 wherein the housing operates under a vacuum in or vacuum-like conditions with the preferred permeate side and sub-ambient pressures ranging from about 0.05 psia to about 14.4 psia.

37. The apparatus of claim 36 wherein the housing operates under a vacuum in or vacuum-like conditions with the preferred permeate side and sub-ambient pressures ranging preferably from about 0.1 psia to about 12.0 psia.

38. The apparatus of claim 1 wherein the hollow fiber membranes are porous.

39. The apparatus of claim 1 wherein the hollow fiber membranes are hydrophobic.

46. A method for separating fresh water from saltwater utilizing the module of claim 39, comprising the steps of:

d. heating a saltwater feed entering the fluid membrane separation module;

e. separating a permeate of water vapour from the saltwater under vacuum or vacuum-like conditions;

f. passing the water vapour through a condenser or blower to increase the pressure of the water vapour;

g. passing the heated water vapour through a heat exchanger to heat the saltwater feed and condense the water vapour; and

h. collecting the condensed water.

40. A fluid separation apparatus comprising:

a. a hollow housing defining a separation chamber, having a feed inlet to permit a fluid mixture to enter into the housing and a permeate outlet to permit the permeate to exit the housing;

b. at least one bundle of hollow fiber membranes contained within the housing having first and second open ends, the first ends being in fluid communication with the permeate outlet; and

c. at least one retentate outlet to permit one or more non-permeate components of the feed fluid mixture to exit the separation chamber;

whereby the feed fluid mixture passes through the separation chamber such that the one or more permeate components of the feed fluid mixture migrate across the walls of the membranes into the lumen of the hollow fiber membranes and exit the housing through the permeate outlet, and one or more of the retentate portions remaining in the housing exits the housing through the retentate outlet.

41. The apparatus of claim 40 wherein the feed fluid mixture is separated into permeate and retentate portions by means of pervaporation, vapour permeation, membrane distillation including vacuum membrane distillation, direct contact membrane distillation, ultra filtration, microfiltration nanofiltration, reverse osmosis, membrane stripping, gas separation or a combination thereof.

42. The apparatus of claim 41 for use in the process of desalination.

43. A method for fluid separation, wherein a feed fluid is separated into permeate and retentate components, comprising the steps of:

a. compressing permeate exiting a permeate outlet of a separation chamber, to create a compressed permeate;

b. transferring heat from the compressed permeate to the feed fluid in a condenser; and

c. maintaining an operating pressure of the condenser by means of a vacuum pump in fluid communication with said condenser.

44. The method of claim 43 for the removal and recovery of fresh water from seawater by means of membrane distillation.

45. The method of claim 44 wherein for the removal of volatile organic compounds from water by means of membrane distillation or pervaporation.