Cross-flow filtration device with filtrate conduit network and method of making same

• US 6,126,833 A
• Filed: 05/06/1999
• Issued: 10/03/2000
• Est. Priority Date: 02/22/1999
• Status: Expired due to Term

• Current Assignee: Serapis Co., Stobbe Tech Holding A/S
• Original Assignee: CeraMem Corp. (Ceramiques Techniques et Industrielles SASU), Stobbe Tech Holding A/S
• Inventors: Stobbe, Per, Goldsmith, Robert L., Bishop, Bruce A.
• Primary Examiner(s): FORTUNA, ANA M
• Application Number:
  US09/306,152
• Time in Patent Office: 516 Days
• Field of Search: 210/500.25, 210/500.26, 210/510.1, 210/500.27, 210/490, 55/524, 55/523
• US Class Current: 210/650
• CPC Class Codes: B01D 2319/04 Elements in parallel
• 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 63/00 Apparatus in general for separation processes using semi-permeable membranes
• CPC Class Codes: F01N 3/0234 using heat exchange means in the exhaust line

Abstract

A cross-flow filtration device which receives a feed stock at a feed end face and separates the feed stock into filtrate and retentate. The device has a structure formed from a plurality of substantially parallel monolith segments of porous material, each segment having a plurality of passageways which extend longitudinally from the feed end face to a retentate end face of the structure. The structure contains a filtrate conduit network comprised of both an intersegment filtrate conduit, formed by the arrangement of the segments, and at least one intrasegment filtrate conduit formed within at least one segment. The filtrate conduit network provides low pressure drop flow paths for filtrate flow through the porous material from the passageways to nearby filtrate conduits, and at least some of the passageways are separated from filtrate conduits by intervening passageways, thereby enabling a high ratio of passageway surface area to volume of the device and a high rate of filtrate removal.

Claims

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

a) a structure containing a substantially parallel arrangement of a plurality of monolith segments of porous material, each segment containing a plurality of passageways extending longitudinally from the feed end face to a retentate end face 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;

b) a filtrate collection zone external to the structure;

c) a filtrate conduit network within the structure for carrying filtrate toward the filtrate collection zone, the filtrate conduit network providing paths of lower flow resistance than that of of alternative flow paths through the porous material;

d) the filtrate conduit network containing an intersegment filtrate conduit defined by the arrangement of the monolith segments and at least one intrasegment filtrate conduit whithin at least one segment, the intrasegment filrate conduit communicating with the intersegment filtrate conduit or otherwise directing the filtrate toward the filtrate collection zone, and wherein the intrasegment filtrate conduit is comprised of a plurality of longitudinal chambers which extend substantially along the entire length of the monolith segment, the chambers being transected by a transverse channel which directs filtrate into the intersegment filtrate conduit or otherwise toward the filtrate collection zone;

e) the filtrate conduit network being isolated from the passageways at both end faces of the structure and at least some of the passageways being separated from the filtrate conduit network by intervening passageways; and

f) means for isolating the filtrate collection one from the feed and retentate ends of the structure.

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

3. The cross-flow filtration device of claim 2 in which the ceramic material is selected from cordierite, alumina, mullite, silica, zirconia, titania, spinel, silicon carbide, or mixtures thereof.

4. The cross-flow filtration device of claim 1 in which the monolith segments are formed into a structure by sealing the ends of the segments at the feed end face and the retentate end face into tube sheets.

5. The cross-flow filtration device of claim 4 in which the means of sealing the ends of the segments is by elastomeric or metallic O-ring or similar seals, rubber boot seals, or organic adhesive or inorganic cement seals.

6. The cross-flow filtration device of claim 1 in which the monolith segments are formed into a unitary structure by bonding the monolith segments to each other along portions of the intersegment filtrate conduit.

7. The cross-flow filtration device of claim 1 in which the filtrate collection zone is disposed along the side of the structure and further includes a 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 collection zone.

8. The cross-flow filtration device of claim 7 in which the barrier means includes an O-ring seal or an elastomeric boot seal.

9. The cross-flow filtration device of claim 1 in which the characteristic dimension of the monolith segments is in the range of two to seven inches.

10. The cross-flow filtration device of claim 1 in which the characteristic dimension of the monolith segments is in the range of three to six inches.

11. The cross-flow filtration device of claim 1 in which the channel includes at least one slot formed in an end face of the monolith segment, the slot being sealed at that end face to isolate the slot from the feed stock and the retentate, and the slot communicating with the intersegment filtrate conduit or toward the filtrate collection zone.

12. The cross-flow filtration device of claim 1 in which the filtrate chambers are formed from at least one row of passageways which extends across the monolith segment.

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

14. The membrane device of claim 13 in which the permselective membrane is selected from the group of membranes suitable for microfiltration, ultrafiltration, nanofiltration, reverse osmosis, gas separations, or pervaporation.

20. A method of separating a feed stream in a cross-flow filtration device into a filtrate and a retentate, which method comprises:

a) providing a cross-flow filtration device of claim 1;

b) introducing a feed stream into the feed end face of the structure and into a plurality of the passageways for separation into a filtrate and retentate;

c) flowing the filtrate from the passageways through the intersegment filtrate conduit and the intrasegment filtrate conduit;

d) collecting the filtrate from the intersegment filtrate conduit and the intrasegment filtration conduit in the external collection zone; and

e) removing the retentate from the retentate end face of the structure.

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

a) a structure containing a substantially parallel arrangement of a plurality of monolith segments of porous material, each segment containing a plurality of passageways extending longitudinally from the feed end face to a retentate end face 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;

b) a filtrate collection zone external to the structure disposed along the side of the structure and further including a 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 collection zone;

c) a filtrate conduit network within the structure for carrying filtrate toward the filtrate collection zone, the filtrate conduit network providing paths of lower flow resistance than that of alternative flow paths through the porous material;

d) the filtrate conduit network containing an intersegment filtrate conduit defined by the arrangement of the monolith segments;

e) the filtrate conduit network further containing at least one intrasegment filtrate conduit within at least one monolith segment, the intrasegment filtrate conduit comprised of a plurality of longitudinal chambers which extend substantially along the entire length of the monolith segment, the chambers being transected by a transverse channel which directs filtrate into the inter-segment filtrate conduit or toward the filtrate collection zone, and the intrasegment filtrate conduit communicating with the intersegment filtrate conduit or otherwise directing filtrate toward the filtrate collection zone; and

f) the filtrate conduit network being isolated from the passageways at both end faces of the structure and at least some of the passageways being separated from the filtrate conduit network by intervening passageways.

16. The cross-flow filtration device of claim 15 in which the characteristic dimension of the monolith segments is in the range of two to seven inches.

17. The cross-flow filtration device of claim 16 further including a permselective membrane applied to the surfaces of the passageways.

18. The membrane device of claim 17 in which the permselective membrane is selected from the group of membranes suitable for microfiltration, ultrafiltration, nanofiltration, reverse osmosis, gas separations, or pervaporation.

19. A method of forming a filtrate conduit network in a structure containing a substantially parallel arrangement of a plurality of monolith segments of porous material, each segment containing a plurality of passageways extending longitudinally from a feed end face to a retentate end face, the surface area of the passageways being at least 100 square feet per cubic foot of the structure, comprising:

a) arranging the monolith segments to form an intersegment filtrate conduit in the space separating the segments, the intersegment filtrate conduit providing a flow path of low resistance for filtrate flow toward a filtrate collection zone;

b) within at least one selected segment, establishing an intrasegment conduit by selecting a plurality of passageways as filtrate chamber passageways to distribute the filtrate chamber passageways among the nonselected passageways in the selected segment to provide low pressure drop flow paths from the nonselected passageways through the porous material to nearby filtrate chamber passageways, and establishing at least one filtrate channel in the selected segment which transects the filtrate chamber passageways, the channel providing a flow path of low resistance for filtrate flow toward the filtrate collection zone or toward the intersegment conduit;

c) sealing the intersegment filtrate conduit at the end faces of the structure to inhibit direct passage of fluid into the intersegment filtrate conduit at the end faces; and

d) sealing all filtrate chamber passageways and filtrate channels exposed at the end faces of the structure to inhibit direct passage of fluid into the intrasegment filtrate conduit.