Submerged cross-flow filtration

• US 20060273007A1
• Filed: 05/26/2006
• Published: 12/07/2006
• Est. Priority Date: 11/02/2004
• Status: Active Grant

• Current Assignee: Evoqua Water Technologies LLC
• Original Assignee: Siemen Water Technologies Corporation (Siemens AG)
• Inventors: Zha, Fufang, Ganzi, Gary C., Beck, Thomas W.
• Granted Patent: US 7,591,950 B2
• Time in Patent Office: Days
• US Class Current: 210/636
• CPC Class Codes: B01D 2313/23 Specific membrane protectors, e.g. sleeves or screens
• CPC Class Codes: B01D 2315/06 Submerged-type; Immersion type
• CPC Class Codes: B01D 2321/185 Aeration
• CPC Class Codes: B01D 2321/2016 Static mixers; Turbulence generators
• CPC Class Codes: B01D 61/18 Apparatus therefor
• CPC Class Codes: B01D 63/024 with a single potted end
• CPC Class Codes: B01D 63/043 with separate tube sheets
• CPC Class Codes: B01D 65/08 Prevention of membrane fouling or of concentration polarisation
• CPC Class Codes: C02F 1/444 by ultrafiltration or microfiltration

Abstract

A membrane filtration module having a plurality of permeable, hollow membranes is disclosed. In use, a pressure differential is applied across the walls of the permeable, hollow membranes when immersed in a liquid suspension containing suspended solids. Some of the liquid suspension passes through the walls of the membranes to be drawn off as clarified liquid or permeate, and at least some of the solids are retained on or in the permeable, hollow membranes or otherwise as suspended solids within the liquid suspension. The module has a shell or similar structure that at least partially surrounds the membrane module and substantially effects retaining at least portion of fluid flowed into the membrane module.

Claims

1. A membrane filtration system comprising:

a vessel having an inlet fluidly connectable to a source of a liquid having solids suspended therein;

a membrane module disposed in the vessel, the membrane module comprising a shell at least partially enclosing a plurality of hollow fiber membranes and at least one scouring port disposed to introduce a scouring fluid comprising a gas, a liquid, or a mixture thereof to the fiber membranes.

2. The membrane filtration system of claim 1, wherein the membrane module further comprises a screen disposed adjacent an enclosed surface of the shell.

3. The membrane filtration system of claim 1, wherein the shell is one of a screen and a baffle plate.

4. The membrane filtration system of claim 1, further comprising a gas and liquid mixing chamber fluidly connected to at least one scouring port.

5. The membrane filtration system of claim 1, wherein at least one scouring port is disposed in an upper potting head of the membrane module.

6. The membrane filtration system of claim 1, wherein the shell has a plurality of liquid exit ports, at least one of the liquid exit port is disposed adjacent to one of an upper potting head and a lower potting head of the membrane module.

7. The membrane filtration system of claim 6, wherein the shell has a liquid exit port medially disposed between the upper and the lower potting head.

8. The membrane module of claim 6, wherein at least one scouring port is disposed in the lower potting head and at least one other scouring port is disposed in the upper potting head.

9. The membrane module of claim 1, wherein the scouring fluid further comprises suspended solids.

10. The membrane module of claim 1, further comprising baffles disposed within the shell.

11. The membrane module of claim 1, firther comprising at least a second scouring port disposed to introduce a second scouring fluid to the plurality of fiber membranes, the second scouring fluid comprising a gas, a liquid, a solid, or a mixture thereof.

12. A membrane module comprising:

a plurality of fiber membranes;

means for introducing a scouring fluid to the plurality of fiber membranes; and

means for retaining the scouring fluid adjacent the plurality of fiber membranes.

13. The membrane module of claim 12, wherein the scouring fluid comprises a gas, liquid, or a mixture thereof.

14. The membrane module of claim 12, wherein the plurality of fiber membranes are arranged in at least two bundles each defining a sub-module.

15. The membrane module of claim 14, further comprising a baffle plate disposed between at least two sub-modules.

16. The membrane module of claim 15, further comprising means for adjusting a gas/liquid ratio of the scouring fluid.

17. A method of purifying water having solids suspended therein, comprising:

introducing the water to a membrane module comprising a shell surrounding a plurality of hollow fiber membranes, the shell having a retentate exit port disposed adjacent to at least one of a lower potting head and an upper potting head;

introducing a scouring fluid into a volume enclosed by the shell, the scouring fluid comprising a gas, a liquid, or a mixture thereof; and

withdrawing permeate through the hollow fiber membranes to produce purified water.

18. The method of claim 17, wherein the scouring fluid further comprises suspended solids.

19. The method of claim 17, wherein the scouring fluid is introduced into the volume through at least one scouring port disposed in at least one of the lower potting head and the upper potting head.

20. The method of claim 17, further comprising withdrawing retentate through the retentate exit port and introducing the withdrawn retentate to a second membrane module.

21. The method of claim 17, further comprising introducing a second scouring fluid into the volume.