Tandem electrolysis cell

Patent metadata

Field	Value
Publication number	US-2021395903-A1
Application number	US-202016933790-A
Country	US
Kind code	A1
Filing date	Jul 20, 2020
Priority date	Jun 18, 2020
Publication date	Dec 23, 2021
Grant date	—

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; 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; and 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.

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 anode is on a second side of the gas barrier, wherein the gas barrier extends below cathode A and the anode, and wherein an opening below the gas barrier allows liquid flow between cathode A and the anode.

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

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

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

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

10 . The tandem electrolysis cell of claim 5 , comprising a chlorine removal port proximate to the anode on a 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 . The tandem electrolysis cell of claim 1 , comprising a water port on the second chamber.

14 . The tandem electrolysis cell of claim 1 , comprising an alkali removal port on the second chamber.

15 . The tandem electrolysis cell of claim 1 , comprising a hydrogen removal port on the second chamber.

16 . 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;
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; and
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; 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.

17 . The system of claim 16 , 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.

18 . The system of claim 16 , comprising a first power supply to provide power to cathode A and the common anode.

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

20 . The system of claim 16 , comprising an ion sensor in the first chamber.

21 . The system of claim 20 , wherein the ion sensor is a sodium electrode.

22 . The system of claim 16 , comprising an ion sensor in the second chamber.

23 . The system of claim 22 , wherein the ion sensor is a pH electrode.

24 . The system of claim 16 , comprising a level sensor in the first chamber, or a level sensor in the second chamber, or both.

25 . The system of claim 16 , comprising a controller to control the tandem electrolysis cell, 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, if so:
turn off a second power supply providing power to cathode B and the common anode; and
turn on a first power supply to provide power to cathode A and the common anode.

26 . The system of claim 25 , wherein the data store comprises instructions to direct the processor to:
close valves for the first electrolysis reaction after turning off the first power supply; and open valves for the second electrolysis reaction prior to turning on the second power supply.

27 . The system of claim 25 , wherein the data store comprises instructions to direct the processor to:
close valves for the second electrolysis reaction after turning off the second power supply; and open valves for the first electrolysis reaction prior to turning on the first power supply.

28 . A method for using a tandem electrolysis cell (TEC) to form hydrogen, oxygen, chlorine, and sodium hydroxide, comprising:
determining if a sodium ion concentration in a first chamber of the TEC is below a threshold, and, while the sodium ion concentration remains below the threshold, iterating:
flowing saline water into a half-cell of a first chamber comprising a first cathode (cathode A);
forming hydrogen at cathode A and oxygen at a common anode; and
monitoring the sodium ion concentration in the first chamber; and
determining if a pH in a second chamber of the TEC is below a threshold, and, while the pH remains below the threshold, iterating:
flowing fresh water into a half-cell of a second chamber comprising a second cathode (cathode B);
forming hydrogen and hydroxide ions at cathode B and oxygen at the common anode; and
monitoring the pH in the first chamber.

29 . The method of claim 28 , comprising, when the sodium ion concentration exceeds the threshold

Assignees

• Saudi Arabian Oil Co

Inventors

• Hammad Ahmad D
• Fadhel Bandar A

Classifications

• Y02E70/30

  Systems combining energy storage with energy generation of non-fossil origin · CPC title

• Y02E60/36

  Hydrogen production from non-carbon containing sources, e.g. by water electrolysis · CPC title

• Y02E10/50

  Photovoltaic [PV] energy · CPC title

• C25B15/031

  pH · CPC title

• C25B15/029

  Concentration · CPC title