Tandem electrolysis cell

Patent metadata

Field	Value
Publication number	US-12000056-B2
Application number	US-202016933790-A
Country	US
Kind code	B2
Filing date	Jul 20, 2020
Priority date	Jun 18, 2020
Publication date	Jun 4, 2024
Grant date	Jun 4, 2024

Abstract

A system and methods for electrolysis of saline solutions are provided. An exemplary system provides a tandem electrolysis cell. The tandem electrolysis cell includes a common enclosure that has two chambers. A first chamber is separated from a second chamber by a cation selective membrane. A common anode and a first cathode (cathode A) are disposed in the first chamber. The first cathode and the common anode are configured to electrolyze a saline solution to hydrogen and oxygen. A second cathode (cathode B) is disposed in the second chamber. The second cathode and the common anode are configured to electrolyze a brine solution in the first chamber to form chlorine and water in the second chamber to form hydrogen and hydroxide ions.

First claim

What is claimed is:

1. A tandem electrolysis cell, comprising:
a common enclosure comprising two chambers, wherein a first chamber is separated from a second chamber by a cation selective membrane;
a common anode disposed in the first chamber, wherein the common anode is operated continuously;
a first cathode (cathode A) disposed in the first chamber, wherein the first cathode and the common anode are configured to electrolyze a saline solution to hydrogen and oxygen, during a first stage of operation;
a second cathode (cathode B) disposed in the second chamber, wherein the second cathode and the common anode are configured to electrolyze a brine solution in the first chamber to form chlorine and water in the second chamber to form hydrogen and hydroxide ions, during a second stage of operation;
a controller to open valves, during the first stage of operation, and close valves, during the second stage of operation on:
a saline inlet port on the first chamber;
an alkali inlet port on the first chamber;
a first hydrogen outlet port proximate to cathode A on the first chamber; and
an oxygen outlet port proximate to the common anode on the first chamber, the oxygen outlet port being attached to the first chamber; and

the controller to open valves, during the second stage of operation, and close valves, during the first stage of operation on:
a water inlet port on the second chamber;
an alkali outlet port on the second chamber;
a second hydrogen outlet port on the second chamber; and
a chlorine outlet port proximate to the common anode on the first chamber, the chlorine outlet port being attached to the first chamber,

wherein the common anode is positioned between cathode A and cathode B, and between the oxygen outlet port and the chlorine outlet port.

2. The tandem electrolysis cell of claim 1 , wherein the enclosure comprises a corrosion resistant inner surface.

3. The tandem electrolysis cell of claim 2 , wherein the corrosion resistant inner surface is glass.

4. The tandem electrolysis cell of claim 1 , wherein the enclosure comprises a ceramic.

5. The tandem electrolysis cell of claim 1 , wherein the first chamber comprises a gas barrier, wherein cathode A is on a first side of the gas barrier and the common anode is on a second side of the gas barrier, wherein the gas barrier extends below cathode A and the common anode, and wherein an opening below the gas barrier allows liquid flow between cathode A and the common anode.

6. The tandem electrolysis cell of claim 5 , wherein the saline inlet port is proximate to cathode A on the first side of the gas barrier.

7. The tandem electrolysis cell of claim 5 , wherein the alkali inlet port is proximate to cathode A on the first side of the gas barrier.

8. The tandem electrolysis cell of claim 5 , wherein the first hydrogen outlet port proximate to cathode A is on the first side of the gas barrier, wherein the first hydrogen outlet port is on a top surface of the enclosure.

9. The tandem electrolysis cell of claim 5 , wherein the oxygen outlet port proximate to the common anode is on the second side of the gas barrier, wherein the oxygen outlet port is on a top surface of the enclosure.

10. The tandem electrolysis cell of claim 5 , wherein the chlorine outlet port proximate to the common anode on the second side of the gas barrier, wherein the chlorine removal port is on a top surface of the enclosure.

11. The tandem electrolysis cell of claim 1 , wherein the cation selective membrane is a sodium permeable membrane.

12. The tandem electrolysis cell of claim 11 , wherein the sodium permeable membrane comprises sulfonated tetrafluoroethylene or polyvinylidene fluoride copolymers or both.

13. A system for electrolyzing seawater, comprising:
a tandem electrolysis cell, comprising:
a common enclosure comprising two chambers, wherein a first chamber is separated from a second chamber by a cation selective membrane;
a common anode disposed in the first chamber, wherein the common anode is operated continuously;
a first cathode (cathode A) disposed in the first chamber, wherein the first cathode and the common anode are configured to electrolyze a saline solution to hydrogen and oxygen in a first electrolysis reaction;
a second cathode (cathode B) disposed in the second chamber, wherein the second cathode and the common anode are configured to electrolyze a brine solution in the first chamber to form chlorine and water in the second chamber to form hydrogen and hydroxide ions in a second electrolysis reaction, wherein the common anode is positioned between cathode A and cathode B;
a controller to open valves, during the first electrolysis reaction, and close valves, during the second electrolysis on:
a saline inlet port on the first chamber;
an alkali inlet port on the first chamber;
a first hydrogen outlet port proximate to cathode A on the first chamber; and
an oxygen outlet port proximate to the common anode on the first chamber, the oxygen outlet port attached to in the first chamber; and

the controller to open valves, during the second electrolysis reaction, and close valves, during the first electrolysis reaction on:
a water inlet port on the second chamber;
an alkali outlet port on the second chamber;
a second hydrogen outlet port on the second chamber; and
a chlorine outlet port proximate to the common anode on the first chamber, the chlorine outlet port attached to the first chamber,
wherein the common anode is positioned between the oxygen outlet port and the chlorine outlet port; and

an atmospheric water producer, wherein the atmospheric water producer comprises:
a solar panel to generate electricity;
a battery to store the electricity, wherein the battery powers the tandem electrolysis cell;
a cooling system powered by the battery, wherein the cooling system harvests atmospheric moisture; and
a water storage tank to collect the harvested atmospheric moisture, wherein the water storage tank provides the water to the second chamber.

14. The system of claim 13 , comprising a sodium hydroxide storage tank to store sodium hydroxide produced during operation of the second chamber for use during operation of the first chamber, the sodium hydroxide storage tank being connected to the alkali inlet port on the first chamber.

15. The system of claim 13 , comprising a first power supply to provide power to cathode A and the common anode.

16. The system of claim 15 , comprising a second power supply to provide power to cathode B and the common anode.

17. The system of claim 13 , comprising an ion sensor in the first chamber.

18. The system of claim 17 , wherein the ion sensor is a sodium electrode.

19. The system of claim 13 , comprising an ion sensor in the second chamber.

20. The system of claim 19 , wherein the ion sensor is a pH electrode.

21. The system of claim 13 , comprising a level sensor in the first chamber, or a level sensor in the second chamber, or both.

22. The system of claim 13 , wherein the controller comprises a processor and a data store, wherein the data store comprises instructions to direct the processor to:
determine if a sodium ion concentration in the first chamber is above a threshold, and, if so:
turn off a first power supply providing power to cathode A and the common anode; and
turn on a second power supply to provide power to cathode B and the common anode; and

determine if a pH in the second chamber is below a threshold, and, i

Assignees

• Saudi Arabian Oil Co

Inventors

• Hammad Ahmad D
• Fadhel Bandar A

Classifications

• C25B1/46 Primary

  in diaphragm cells · CPC title

• B01D53/265

  by refrigeration (condensation) · CPC title

• C25B9/23

  comprising ion-exchange membranes in or on which electrode material is embedded · CPC title

• C25B9/65

  Means for supplying current; Electrode connections; Electric inter-cell connections · CPC title

• C25B15/02

  Process control or regulation · CPC title