SIMPLE GAS SCOURING METHOD AND APPARATUS

• US 20100000941A1
• Filed: 12/22/2005
• Published: 01/07/2010
• Est. Priority Date: 12/24/2004
• Status: Active Grant

• Current Assignee: Siemens Water Technologies LLC (Evoqua Water Technologies LLC)
• Original Assignee: Siemen Water Technologies Corporation (Siemens AG)
• Inventors: Muller, Joachim
• Granted Patent: US 8,758,622 B2
• Time in Patent Office: Days
• US Class Current: 210/636
• CPC Class Codes: B01D 2313/26 Specific gas distributors or gas intakes
• CPC Class Codes: B01D 2315/08 Fully permeating type; Dead-end filtration
• CPC Class Codes: B01D 2321/16 Use of chemical agents
• CPC Class Codes: B01D 2321/185 Aeration
• CPC Class Codes: B01D 61/20 Accessories; Auxiliary operations
• CPC Class Codes: B01D 65/02 Membrane cleaning or sterilisation ; Membrane regeneration
• 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 2301/063 Underpressure, vacuum
• CPC Class Codes: C02F 2303/16 Regeneration of sorbents, filters

Abstract

A method of cleaning a membrane (6) in a membrane filtration system by flowing gas bubbles past the surfaces of the membrane (6) to scour accumulated solids therefrom. The method includes flowing a liquid past a supply of gas; creating a reduced pressure within the liquid flow to cause a flow of gas from the supply of gas (9) into the liquid flow and form gas bubbles therein and then flowing the liquid containing the gas bubbles past the surfaces of the membrane (6) to scour the surfaces thereof. Apparatus for performing the method is also disclosed.

Claims

1. A method of cleaning a membrane in a membrane filtration system by flowing gas bubbles past the surfaces of said membrane to scour accumulated solids therefrom, the method comprising the steps of:

a) flowing a liquid past a supply of gas;

b) creating a reduced pressure within said liquid flow to cause a flow of gas from said supply of gas into said liquid flow and form gas bubbles therein; and

c) flowing said liquid containing said gas bubbles past the surfaces of said membrane to scour the surfaces thereof

wherein said creating of reduced pressure within said liquid flow is responsive to an increase in resistance in said membrane.

2. A method according to claim 1 wherein the reduced pressure is created in an eductor or venturi device having said liquid flowing therethrough.

3. A method according to claim 1 wherein the liquid includes feed liquid supplied to the membrane filtration system.

4. A method according to claim 1 including providing valve means responsive to said increase in resistance of said membrane to increase the flow of said liquid through said device.

5. A method according to claim 1 wherein during normal filtration operation of the membrane filtration system, the flow rate of said liquid is selected such that minimal pressure reduction is created.

6. A method according to claim 5 including providing further valve means to prevent flow of gas into said liquid flow during said normal filtration operation.

7. A method according to claim 6 wherein said further valve means is responsive to said flow rate of said liquid flow.

8. A method according to claim 1 further including the steps of flowing a liquid past a supply of chemical cleaning fluid such that said reduced pressure within said liquid flow causes a flow of said chemical cleaning fluid from said supply of chemical cleaning fluid into said liquid flow.

9. Apparatus for cleaning a membrane in a membrane filtration system by flowing gas bubbles past the surfaces of said membrane to scour accumulated solids therefrom, the apparatus comprising the steps of:

a) means for flowing a liquid past a supply of gas;

b) means responsive to an increase in resistance of said membrane for creating a reduced pressure within said liquid flow to cause a flow of gas from said supply of gas into said liquid flow and form gas bubbles therein; and

c) means for flowing said liquid containing said gas bubbles past the surfaces of said membrane to scour the surfaces thereof.

10. Apparatus according to claim 9 wherein the means for creating a reduced pressure is an eductor or venturi device having said liquid flowing therethrough.

11. Apparatus according to claim 9 wherein the liquid includes feed liquid supplied to the membrane filtration system.

12. Apparatus according to claim 10 further including valve means responsive to said increase in resistance of said membrane to increase the flow of said liquid through said device.

13. Apparatus according to claim 9 wherein during normal filtration operation of the membrane filtration system, the flow rate of said liquid is selected such that minimal pressure reduction is created.

14. Apparatus according to claim 13 including further valve means to prevent flow of gas into said liquid flow during said normal filtration operation.

15. Apparatus according to claim 14 wherein said further valve means is responsive to said flow rate of said liquid flow.

16. Apparatus according to claim 9 further including means for flowing a liquid past a supply of chemical cleaning fluid such that said reduced pressure within said liquid flow causes a flow of said chemical cleaning fluid from said supply of chemical cleaning fluid into said liquid flow.

17. Apparatus according to claim 16 wherein said means for flowing a liquid includes said eductor or venture device.