Cross current staged reverse osmosis

Patent metadata

Field	Value
Publication number	US-12065370-B2
Application number	US-202217839863-A
Country	US
Kind code	B2
Filing date	Jun 14, 2022
Priority date	Jun 6, 2016
Publication date	Aug 20, 2024
Grant date	Aug 20, 2024

Abstract

Systems and processes for purifying and concentrating a liquid feed stream are disclosed. In the systems, the concentrated liquid output from the high pressure side of a reverse osmosis stage is used as the draw solution in the low pressure side of the reverse osmosis stage in a configuration called osmotically assisted reverse osmosis. This reduces the osmotic pressure differential across the membrane, permitting high solute concentrations to be obtained, hastening the purification of the liquid. Reduced system pressures are also obtained by arranging multiple osmotically assisted reverse osmosis stages in a cross-current arrangement. Overall system energy consumption is reduced compared to conventional thermal processes for high concentration streams.

First claim

The invention claimed is:

1. A purification system, comprising:
a first reverse osmosis stage having a high pressure side and a low pressure side; and
a second reverse osmosis stage having a high pressure side and a low pressure side;
wherein the high pressure side of the first reverse osmosis stage outputs a yield stream that is split into a recycle stream and a concentrate stream;
wherein the low pressure side of the first reverse osmosis stage receives the recycle stream and outputs a purified stream;
wherein the high pressure side of the second reverse osmosis stage receives the purified stream from the first reverse osmosis stage and outputs a reject stream which is recycled to the high pressure side of the first reverse osmosis stage; and
wherein the low pressure side of the second reverse osmosis stage outputs a final permeate product.

2. The system of claim 1 , comprising a valve or energy recovery device through which the yield stream passes before being split into the recycle stream and the concentrate stream.

3. The system of claim 1 , further comprising a pressurizing means for increasing the pressure of the purified stream.

4. The system of claim 1 , wherein the first reverse osmosis stage has a plurality of reverse osmosis modules.

5. The system of claim 4 , wherein a low pressure side outlet of each reverse osmosis module in the first reverse osmosis stage outputs a yield stream, the yield streams being combined to form the purified stream.

6. The system of claim 4 , wherein for each reverse osmosis module in the first reverse osmosis stage, a feed stream is split into a feed input stream and a feed bypass stream, the feed input stream is fed into a high pressure side of the reverse osmosis module, and the feed bypass stream is fed into a low pressure side of the reverse osmosis module.

7. The system of claim 6 , wherein fluid flow through each reverse osmosis module in the first reverse osmosis stage is counter-current.

8. The system of claim 6 , wherein fluid flow through each reverse osmosis module in the first reverse osmosis stage is co-current.

9. The system of claim 1 , further comprising a liquid feed stream to the system.

10. The system of claim 9 , further comprising a means for pretreating the liquid feed stream upstream of the system.

11. The system of claim 10 , wherein the means for pretreating the liquid feed stream includes a capacitive deionization system or a forward osmosis system.

12. The system of claim 11 , further comprising a sonication system for receiving a concentrate from the capacitive deionization system.

13. The system of claim 1 , further comprising a pressure retarded osmosis stage having a high pressure side and a low pressure side,
wherein the high pressure side of the pressure retarded osmosis stage receives a high pressure concentrate stream and outputs a high pressure diluate;
wherein the low pressure side of the pressure retarded osmosis stage receives a dilute solution and outputs a concentrated solution; and
wherein the high pressure concentrate stream is produced by pressurizing the concentrate stream of the first reverse osmosis stage.

14. The system of claim 13 , wherein the high pressure diluate feeds a pressure exchanger that produces the high pressure concentrate stream.

15. The system of claim 13 , wherein the high pressure diluate feeds an energy recovery device.

16. The system of claim 13 , wherein the pressure retarded osmosis stage is operated so that fluid flow through the high pressure side and the low pressure side is counter-current.

17. The system of claim 13 , wherein the pressure retarded osmosis stage is operated so that fluid flow through the high pressure side and the low pressure side is co-current.

Assignees

• Battelle Memorial Institute

Inventors

• Blohm Kurt
• Peterson Richard
• Lane Ann E
• Winecki Slawomir
• Argumedo Darwin

Classifications

• C02F2303/10

  Energy recovery · CPC title

• C02F2301/08

  Multistage treatments, e.g. repetition of the same process step under different conditions · CPC title

• C02F2301/046

  Recirculation with an external loop · CPC title

• C02F2103/08

  Seawater, e.g. for desalination · CPC title

• C02F1/4691

  Capacitive deionisation · CPC title