Half-cell electrochemical configurations for self-cleaning electrochlorination devices

Patent metadata

Field	Value
Publication number	US-11795074-B2
Application number	US-201816491728-A
Country	US
Kind code	B2
Filing date	Mar 6, 2018
Priority date	Mar 6, 2017
Publication date	Oct 24, 2023
Grant date	Oct 24, 2023

Abstract

An electrochemical cell including a first chamber having an anode, a second chamber having a cathode, at least one ionic connection between the first chamber and the second chamber, such that liquid electrolyte from the first chamber is prevented from mixing with liquid electrolyte in the second chamber is provided. The first chamber and the second chamber can be arranged in parallel and positioned remotely from each other. An electrochemical system including the electrochemical cell, and first and second sources of saline aqueous solutions is also provided. Water treatment systems are also provided. A method of operating an electrochemical cell including introducing first and second saline aqueous solutions into first and second chambers of the electrochemical cell, and applying a current across the anode and the cathode to generate first and second products, respectively is also provided. A method of facilitating operation of an electrochemical cell is also provided.

First claim

What is claimed is:

1. An electrochemical cell comprising:
a first chamber having an inlet and an outlet;
an anode disposed within the first chamber;
a second chamber having an inlet and an outlet;
a cathode disposed within the second chamber;
a controller configured to apply an electrical current across the anode and cathode and to mitigate generation of hydrogen gas within the electrochemical cell by reversing a flow of the electrical current at a periodic rate selected to prevent voltage across the anode and cathode from rising to a level at which the hydrogen gas is generated in the electrochemical cell; and
at least one ionic connection between the first chamber and the second chamber, the ionic connection constructed and arranged to prevent liquid electrolyte in the first chamber from mixing with liquid electrolyte in the second chamber, the first chamber and the second chamber arranged in parallel and positioned remotely from each other.

2. The electrochemical cell of claim 1 , wherein the ionic connection comprises at least one of a salt bridge and an ion-permeable membrane.

3. The electrochemical cell of claim 2 , wherein the ion-permeable membrane is a selectively permeable to monovalent ions.

4. The electrochemical cell of claim 2 , wherein the resistance per area of the ion-permeable membrane is 1.0 Ω/mm 2 or less.

5. The electrochemical cell of claim 2 , wherein the resistance per area of the ion-permeable membrane is 0.1 Ω/mm 2 or less.

6. The electrochemical cell of claim 1 , wherein the liquid electrolyte in the first chamber and the liquid electrolyte in the second chamber have different compositions.

7. The electrochemical cell of claim 6 , wherein the liquid electrolyte in the first chamber and the liquid electrolyte in the second chamber have different salinities.

8. The electrochemical cell of claim 1 , wherein the first chamber further comprises a recirculating channel extending between the outlet of the first chamber and the inlet of the first chamber and configured to circulate electrolyte between the outlet of the first chamber and the inlet of the first chamber without mixing with electrolyte from the second chamber.

9. The electrochemical cell of claim 8 , wherein the second chamber is a single-pass chamber.

10. The electrochemical cell of claim 1 , wherein the second chamber further comprises a recirculating channel extending between the outlet of the second chamber and the inlet of the second chamber.

11. The electrochemical cell of claim 1 , further comprising a shared electrolyte channel which splits into a first channel fluidly connected to the first chamber and a second channel fluidly connected to the second chamber.

12. The electrochemical cell of claim 1 , wherein the first chamber is disposed within a first housing and the second chamber is disposed within a second housing separate from the first housing.

13. A water treatment system comprising the electrochemical cell of claim 1 in fluid communication with a source of water and a source of an oxidant, and constructed and arranged to electrochemically generate H 2 O 2 from the water.

14. A seawater treatment system comprising the electrochemical cell of claim 1 in fluid communication with a source of seawater and constructed and arranged to electrochemically generate NaOCl from the seawater.

15. An electrochemical system comprising:
an electrochemical cell including:
a first chamber having an inlet, an outlet, and an anode disposed within the first chamber;
a second chamber having an inlet, an outlet, and a cathode disposed within the second chamber and positioned remotely from the first chamber;
a controller configured to apply an electrical current across the anode and cathode and to mitigate generation of hydrogen gas within the electrochemical cell by reversing a flow of the electrical current at a periodic rate selected to prevent voltage across the anode and cathode from rising to a level at which the hydrogen gas is generated in the electrochemical cell;
at least one ionic connection between the first chamber and the second chamber;
a first source of a saline aqueous solution having an outlet fluidly connectable to the inlet of the first chamber; and
a second source of a saline aqueous solution having an outlet fluidly connectable to the inlet of the second chamber.

16. The electrochemical system of claim 15 , wherein the first source of the saline aqueous solution has a different salinity than the second source of the saline aqueous solution.

17. The electrochemical system of claim 16 , wherein the first source of the saline aqueous solution comprises seawater and the second source of the saline aqueous solution comprises brine.

18. The electrochemical system of claim 16 , further comprising a recirculation line extending between the outlet and the inlet of the first chamber.

19. The electrochemical system of claim 15 , further comprising a source of an oxidizing agent fluidly connectable to the second source of the saline aqueous solution upstream of the electrochemical cell.

20. The electrochemical system of claim 19 , further comprising:
a sensor constructed and arranged to measure at least one of a concentration of dissolved oxygen, a concentration of dissolved hydrogen, and hydrogen gas in the second chamber; and
a controller configured to regulate a rate of introduction of the oxidizing agent into the second source of the saline aqueous solution responsive to at least one of the concentration of dissolved oxygen, the concentration of dissolved hydrogen, and the hydrogen gas being outside a predetermined range.

21. The electrochemical system of claim 20 , wherein the controller is configured to regulate the rate of introduction of the oxidizing agent into the second source of the saline aqueous solution in an amount sufficient to prevent formation of hydrogen gas at the cathode during operation of the electrochemical cell.

22. The electrochemical system of claim 19 , wherein the source of the oxidizing agent is constructed and arranged to deliver hydrogen peroxide to the second source of the saline aqueous solution from the outlet of the second chamber.

23. The electrochemical system of claim 15 , wherein at least one of the first source of the saline aqueous solution and the second source of the aqueous solution comprises seawater, brackish water, or brine.

Assignees

• Evoqua Water Tech Llc

Inventors

• Gu George Y
• Dukes Simon Paul
• Griffis Joshua
• Shaw Michael J

Classifications

• C02F1/4674 Primary

  with halogen or compound of halogens, e.g. chlorine, bromine · CPC title

• C02F1/46104

  Devices therefor; Their operating or servicing · CPC title

• C02F2103/08

  Seawater, e.g. for desalination · CPC title

• C02F2201/4613

  Inversing polarity · CPC title

• C02F2201/4614

  Current · CPC title