Cross-flow filtration device with filtrate flow conduits and method of forming same

• US 4,781,831 A
• Filed: 04/02/1987
• Issued: 11/01/1988
• Est. Priority Date: 12/19/1986
• Status: Expired due to Term

• Current Assignee: Corning Incorporated
• Original Assignee: CeraMem Corp. (Ceramiques Techniques et Industrielles SASU)
• Inventors: Goldsmith, Robert L.
• Primary Examiner(s): SPEAR JR, FRANK
• Application Number:
  US07/033,572
• Time in Patent Office: 579 Days
• Field of Search: 210/433.2, 210/496, 210/321.1, 210/652, 210/247, 210/321.89, 210/321.82, 210/456
• US Class Current: 210/247
• CPC Class Codes: B01D 2319/04 Elements in parallel
• CPC Class Codes: B01D 29/05 supported
• CPC Class Codes: B01D 29/52 in parallel connection
• CPC Class Codes: B01D 29/945 for continuously discharging concentrated liquid
• CPC Class Codes: B01D 46/005 Crossflow filtration, i.e. having an inlet and two outlets
• CPC Class Codes: B01D 46/24 Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
• 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 63/06 Tubular membrane modules
• CPC Class Codes: B01D 63/061 Manufacturing thereof
• CPC Class Codes: B01D 63/066 with a porous block having membrane coated passages

Abstract

A cross-flow filtration device which separates a feed stock into filtrate and retentate, including a structure of porous material which defines a plurality of passageways extending longitudinally from the feed end of the structure to a retentate end, and a number of filtrate conduits within the structure for carrying filtrate from within the structure toward a filtrate collection zone. The filtrate conduits provide paths of lower flow resistance than that of alternative flow paths through the porous material, and the structure is constructed such that the filtrate conduits are distributed among the passageways to provide low pressure drop flow paths for filtrate flow from the passageways through the porous material to nearby filtrate conduits. The cross-flow filtration device can also be utilized as a membrane support for a device for cross-flow microfiltration, ultrafiltration, reverse osmosis, gas separations or pervaporation. Also disclosed is a method of making such a cross-flow filtration device.

Claims

1. A cross-flow filtration device for receiving a feed stock at a feed end and for separating the feed stock into filtrate and retentate, comprising:

a structure of porous material defining a plurality of passageways extending longitudinally from the feed end to a retentate end of the structure through which the feed stock flows to pass retentate from the device, the surface area of the passageways being at least 100 square feet per cubic foot of the structure;

a filtrate collection zone disposed along at least one side of the structure;

a plurality of filtrate conduits within the structure for carrying filtrate from within the structure toward the filtrate collection zone, the filtrate conduits providing paths of lower flow resistance than that of alternative flow paths through the porous material;

the filtrate conduits being distributed among the passageways to provide low pressure drop flow paths for filtrate flow through the porous material from the passageways to nearby filtrate conduits; and

means for isolating the filtrate collection zone from the feed and retentate ends of the structure.

2. The cross-flow filtration device of claim 1 in which the structure is a single monolith and the filtrate conduits are formed within it.

3. The cross-flow filtration device of claim 2 in which the filtrate conduits extend longitudinally from the feed end to the retentate end of the structure.

4. The cross-flow filtration device of claim 2 in which the monolith has a skin through which the filtrate conduits direct the filtrate to the filtrate collection zone.

5. The cross-flow filtration device of claim 4 in which the monolith skin includes a plurality of openings to enhance transport of the filtrate from the filtrate conduits to the filtrate collection zone.

6. The cross-flow filtration device of claim 2 in which at least one of the filtrate conduits extends longitudinally together with the passageways along at least a portion of its length.

7. The cross-flow filtration device of claim 6 in which the filtrate conduit includes at least one channel extending transversely from the longitudinal portion to the filtrate collection zone for directing filtrate to the filtrate collection zone.

8. The cross-flow filtration device of claim 7 in which the longitudinal portion includes a plurality of longitudinal chambers which connect with the channel.

9. The cross-flow filtration device of claim 7 in which the channel is a slot formed in one end of the monolith.

10. The cross-flow filtration device of claim 7 in which the channel is a hole formed in the monolith.

11. The cross-flow filtration device of claim 7 in which the filtrate conduit includes at least one channel formed at both the feed end and the retentate end of the device.

12. The cross-flow filtration device of claim 1 in which the structure is constructed from a plurality of separate segments of the porous material, each segment having a plurality of the passageways extending along it, and the segments are arranged to define the filtrate conduits among them.

13. The cross-flow filtration device of claim 12 in which the segments are slabs of substantially rectangular cross section and are generally parallel to each other.

14. The cross-flow filtration device of claim 1 in which the structure includes barrier means, disposed at the feed and retentate ends of the structure, for inhibiting direct passage of the feed stock and retentate into the filtrate conduits.

15. The cross-flow filtration device of claim 1 in which the surface area of the passageways is from about 200 to 800 square feet per cubic foot of the structure.

16. The cross-flow filtration device of claim 1 in which the passageways are generally parallel.

17. The cross-flow filtration device of claim 16 in which the passageways are arranged between the filtrate conduits in successive layers.

18. The cross-flow filtration device of claim 1 in which the filtrate conduits are filled with a packing material having a lower flow resistance than that of the porous material to provide mechanical support for the filtrate conduits.

19. The cross-flow filtration device of claim 1 in which the filtrate conduits are substantially equally spaced and generally parallel.

20. The cross-flow filtration device of claim 1 in which the porous structure material is a ceramic material.

21. The cross-flow filtration device of claim 20 in which the ceramic material is selected from cordierite, alumina, mullite, silica, zirconia, titania, spinel, silicon carbide, or mixtures thereof.

22. The cross-flow filtration device of claim 1 in which the porous material has a porosity of about 20 to 60 percent.

23. The cross-flow filtration device of claim 1 in which the porous material has a mean pore size of about 0.1 to 20 microns.

24. The cross-flow filtration device of claim 1 further including a permselective membrane applied to the surfaces of the passageways.

25. The cross-flow filtration device of claim 24 in which the permselective membrane is selected from the group of membranes suitable for cross-flow microfiltration, ultrafiltration, reverse osmosis, gas separations, or pervaporation.

26. The cross-flow filtration device of claim 1 in which the filtrate conduits in combination with the structure provide a mean permeability of at least 1000 gallons per day per square foot passageway surface area for water at 25 degrees Centigrade supplied to the pasageways at a pressure differential between the passageways and the filtrate collection zone substantially similar to that selected for the feed stock.

27. The cross-flow filtration device of claim 1 in which the filtrate collection zone surrounds all sides of the structure.

28. A method of forming filtrate conduits in a monolith of porous material having a plurality of passageways extending from an upstream end to a downstream end of the monolith, comprising:

selecting one or more of the passageways as filtrate conduit passageways for carrying filtrate from within the monolith to a filtrate collection zone, disposed along at least one side of the monolith, to distribute the filtrate conduit passageways among the non-selected passageways to provide low pressure drop flow paths from the non-selected passageways through the porous material to nearby filtrate conduit passageways, the surface area of the passageways being at least 100 square feet per cubic foot of the structure;

establishing one or more channels to connect the filtrate conduit passageways to the filtrate collection zone; and

sealing the filtrate conduit passageways to inhibit direct passage of fluid into the filtrate conduit passageways and the filtrate collection zone.

29. The method of claim 28 in which the filtrate conduit passageways are sealed at the upstream and downstream ends of the monolith.

30. The method of claim 28 in which establishing each channel includes cutting a slot in at least one end of the monolith to form that channel.

31. The method of claim 28 in which establishing each channel includes forming a hole through the monolith to form that channel.

32. The method of claim 28 in which selecting includes designating a plurality of sets of passageways as filtrate conduit passageways, each set including a row of adjoining passageways.

33. The method of claim 32 in which the sets of filtrate conduit passageways are substantially equally spaced and parallel.

34. The method of claim 32 in which each set of filtrate conduit passageways and associated channel extends across the monolith.

35. The method of claim 28 in which selecting includes providing a surface area of non-selected passageways of at least 100 square feet per cubic foot of the monolith.

36. The method of claim 35 further including providing the monolith with a mean permeability of at least 1000 gallons per day per square foot geometric area for water at 25 degrees Centigrade supplied to the passageways at a pressure differential between the passageways and the filtrate collection zone substantially similar to that selected for the feed stock.

37. A cross-flow filtration device for receiving a feed stock at a feed end and for separating the feed stock into filtrate and retentate, comprising:

a single monolith of porous material defining a plurality of passageways extending longitudinally from the feed end to a retentate end of the monolith through which the feed stock flows to pass retentate from the device;

a filtrate collection zone disposed along at least one side of the monolith;

a plurality of filtrate conduits formed within the monolith for carrying filtrate from within the monolith toward the filtrate collection zone, the filtrate conduits providing flow paths of lower flow resistance than that of alternative flow paths through the porous material;

the filtrate conduits being distributed among the passageways to provide low pressure drop flow paths for filtrate flow through the porous material from the passageways to nearby filtrate conduits;

the surface area of the passageways being at least 100 square feet per cubic foot of the monolith; and

means for isolating the filtrate collection zone from the feed and retentate ends of the monolith.