Sea water desalination system

Patent metadata

Field	Value
Publication number	US-9340436-B2
Application number	US-201313863948-A
Country	US
Kind code	B2
Filing date	Apr 16, 2013
Priority date	Apr 16, 2013
Publication date	May 17, 2016
Grant date	May 17, 2016

Abstract

There is disclosed an electrochemical cell for treating water comprising at least one water chamber configured to hold water to be treated; at least one redox electrode comprising reactants capable of accepting and having a reversible redox reaction with at least one negative ion in the water; at least one intercalation electrode capable of accommodating and intercalating at least one positive ion in the water, wherein the intercalation electrode is immersed in the water chamber or separated from the water chamber by an optional porous separator; and an anion exchange membrane separating the redox electrode from the water chamber. The cell can be used to desalinate water having a wide range of salinities, including sea water, and brackish water. The cell can also be used to collect salt, which can subsequently used to concentrate industrial brine. Methods for using the electrochemical cell to treat water, such as desalinate saline solutions are disclosed. Also disclosed are methods for concentrated brine production for making salt.

First claim

What is claimed is:

1. An electrochemical cell for the treatment of water, comprising:
at least one water chamber configured to hold water to be treated;
at least one redox electrode comprising ferrous chloride solution in hydrochloric acid capable of accepting and having a reversible redox reaction with chloride ions in the water;
at least one intercalation electrode capable of accommodating and intercalating at least one positive ion in the water, wherein the intercalation electrode is immersed in the water chamber or separated from the water chamber by an optional porous separator; and
an anion exchange membrane separating the redox electrode from the water chamber.

2. The electrochemical cell of claim 1 , wherein the intercalation electrode comprises manganese dioxide.

3. The electrochemical cell of claim 2 , wherein said manganese dioxide is in alpha or delta crystallographic form.

4. The electrochemical cell of claim 1 , further comprising a power supply capable of applying a voltage sufficient to make the redox electrode more positive than the intercalation electrode.

5. The electrochemical cell of claim 1 , wherein said chamber configured to contain water to be treated comprises water having a salinity of at least 500 mg/L to be desalinated.

6. The electrochemical cell of claim 1 , wherein said chamber configured to contain water to be treated comprises water having a salinity of at less than 500 mg/L to be resalinated.

7. The electrochemical cell of claim 1 , further comprising at least one outlet for the removal of said treated water.

8. The electrochemical cell of claim 1 , further comprising at least one chamber for the collection of salt.

9. A method of desalinating water, said method comprising flowing water having a salinity of at least 500 mg/L through an electrochemical desalination cell comprising:
at least one water chamber configured to hold water to be treated;
at least one redox electrode comprising reactants capable of accepting and having a reversible redox reaction with at least one negative ion in the water;
at least one intercalation electrode capable of accommodating and intercalating at least one positive ion in the water, wherein the intercalation electrode is immersed in the water chamber or separated from the water chamber by an optional porous separator; and
an anion exchange membrane separating the redox electrode from the water chamber,
wherein said water exits said anion exchange membrane with a salinity of less than 500 mg/L;
wherein the at least one redox electrode comprises ferrous chloride solution in hydrochloric acid;
wherein the at least one negative ion in the water comprises chloride ions; and
wherein the redox electrode comprising ferrous chloride solution in hydrochloric acid is capable of accepting and having a reversible redox reaction with chloride ions in the water.

10. The method of claim 9 , further comprising controlling the flow of at least one of the reactants, the water to be desalinated, or the desalinated water, in and out of the cell according to an algorithm.

11. The method of claim 9 , wherein said water that exits the anion exchange membrane has a salinity of ranging from 10-250 mg/L.

12. The method of claim 9 , further comprising resalinating a previously desalinated water by connecting the redox electrode and the intercalation electrode to an electronic load.

13. The method of claim 12 , wherein the resalinating supplies energy to the electronic load.

14. The method of claim 9 , wherein the water to be desalinated has a salinity ranging from 1000-35,000 mg/L.

15. The method of claim 9 , further comprising applying a voltage with a power supply sufficient to make the redox electrode more positive than the intercalation electrode.

16. The method of claim 9 , further comprising collecting the salt removed by said desalination.

17. The method of claim 16 , wherein the collected salt is subsequently added to industrial brine.

Assignees

• Palo Alto Res Ct Inc

Inventors

• Sahu Saroj Kumar
• Torres Francisco E

Classifications

• C02F1/4695

  electrodeionisation · CPC title

• C02F1/4691

  Capacitive deionisation · CPC title

• C02F2103/08

  Seawater, e.g. for desalination · CPC title

• C02F1/4693 Primary

  electrodialysis · CPC title

• C02F1/4604 Primary

  for desalination of seawater or brackish water · CPC title