Electrochemical module configuration for the continuous acidification of alkaline water sources and recovery of CO2 with continuous hydrogen gas production

Patent metadata

Field	Value
Publication number	US-10450661-B2
Application number	US-201715614855-A
Country	US
Kind code	B2
Filing date	Jun 6, 2017
Priority date	Feb 28, 2013
Publication date	Oct 22, 2019
Grant date	Oct 22, 2019

Abstract

A method for using an electrochemical cell to continuously acidify alkaline water sources and recover carbon dioxide with simultaneous continuous hydrogen gas production. The electrochemical cell has a center compartment, an electrolyte-free anode compartment having a mesh anode in direct contact with an ion permeable membrane, an endblock in direct contact with the anode where the endblock provides a gas escape route behind the anode, an electrolyte-free cathode compartment having a mesh cathode in direct contact with an ion permeable membrane, and an endblock in direct contact with the cathode where the endblock provides a gas escape route behind the cathode. Current applied to the electrochemical cell for generating hydrogen gas also lowers the pH of the alkaline water to produce carbon dioxide with no additional current or power.

First claim

What is claimed as new and desired to be protected by Letters Patent of the United States is:

1. A method for continuously acidifying alkaline water sources and recovering carbon dioxide with continuous hydrogen gas production, comprising:
passing an alkaline water source comprising carbonate, bicarbonates, or both through an electrochemical cell comprising
a center compartment in fluid communication with the alkaline water source;
a first ion permeable membrane adjacent to the center compartment;
a mesh anode in direct contact with a screen that is in direct contact with the first ion permeable membrane, wherein the mesh anode allows for polarity reversal, and wherein the first ion permeable membrane is an active mediator for protons produced at the mesh anode to transfer into the center compartment in the absence of an electrolyte or an ion exchange resin in the anode compartment;
a first end block in direct contact with the mesh anode, wherein the first end block comprises channels for a gas escape route behind the mesh anode;
a second ion permeable membrane adjacent to the center compartment, wherein the first and second ion permeable membranes are on opposite sides of the center compartment;
a mesh cathode in direct contact with a screen that is in direct contact with the second ion permeable membrane, wherein the mesh cathode allows for polarity reversal, and wherein the second ion permeable membrane is an active mediator for cations in the center compartment that have been displaced by the protons from the anode to transfer into a cathode compartment in the absence of an electrolyte or an ion exchange resin in the cathode compartment; and
a second end block in direct contact with the mesh cathode wherein the second end block comprises channels for a gas escape route behind the mesh cathode;

wherein when the alkaline water source is passed through the electrochemical cell, sodium ions transfer through the second ion permeable membrane and are replaced by hydrogen ions.

2. The method of claim 1 , wherein each ion permeable membrane comprises a cross-linked polymer backbone with sulfonic acid groups attached thereto.

3. The method of claim 1 , wherein the mesh anode and mesh cathode each comprise a material capable of promoting both water reduction and water oxidation reactions.

4. The method of claim 1 , wherein the center compartment is empty.

5. The method of claim 1 , wherein the center compartment contains material that allows up to 100% of the center compartment to be conductive when filled with alkaline water.

6. The method of claim 1 , wherein the pH of the alkaline water source can be reduced to 6.0 or below.

7. The method of claim 1 , wherein when current is applied to the electrochemical cell to generate hydrogen gas, this current produces the protons at the mesh anode that lower the pH of the alkaline water comprising carbonates, bicarbonates, or both to produce carbon dioxide with no additional current or power.

8. The method of claim 1 , wherein the cell is optimized by changing the conductivity of at least one ion permeable membrane, the distance between the electrodes, the electrode surface area, or any combination thereof.

9. A method for continuously acidifying alkaline water sources and recovering carbon dioxide with continuous hydrogen gas production, comprising:
passing an alkaline water source comprising carbonate, bicarbonates, or both through an electrochemical cell comprising
a center compartment in fluid communication with the alkaline water source;
a first ion permeable membrane adjacent to the center compartment;
an electrolyte-free anode compartment comprising a mesh anode in direct contact with a screen that is in direct contact with the first ion permeable membrane, wherein the mesh anode allows for polarity reversal;
a first end block in direct contact with the mesh anode, wherein the first end block comprises channels for a gas escape route behind the mesh anode;
a second ion permeable membrane adjacent to the center compartment, wherein the first and second ion permeable membranes are on opposite sides of the center compartment;
an electrolyte-free cathode compartment comprising a mesh cathode in direct contact with a screen that is in direct contact with the second ion permeable membrane, wherein the mesh cathode allows for polarity reversal;
a second end block in direct contact with the mesh cathode, wherein the second end block comprises channels for a gas escape route behind the mesh cathode; and
means to control the pressure differential between the center compartment and both the anode and cathode compartments;

wherein when the alkaline water source is passed through the electrochemical cell, sodium ions transfer through the second ion permeable membrane and are replaced by hydrogen ions.

10. The method of claim 9 , wherein each ion permeable membrane comprises a cross-linked polymer backbone with sulfonic acid groups attached thereto.

11. The method of claim 9 , wherein the mesh anode and mesh cathode each comprise a material capable of promoting both water reduction and water oxidation reactions.

12. The method of claim 9 , wherein the center compartment is empty.

13. The method of claim 9 , wherein the center compartment contains material that allows up to 100% of the center compartment to be conductive when filled with alkaline water.

14. The method of claim 9 , wherein a center compartment outlet pressure is maintained from 2 to 5 psi above an outlet pressure for both the anode and cathode compartments.

15. The method of claim 9 , wherein the pH of the alkaline water source can be reduced to 6.0 or below.

16. The method of claim 9 , wherein when current is applied to the electrochemical cell to generate hydrogen gas, this current produces the protons at the mesh anode that lower the pH of the alkaline water sources comprising carbonates, bicarbonates, or both to produce carbon dioxide with no additional current or power.

17. The method of claim 9 , wherein the cell is optimized by changing the conductivity of at least one ion permeable membrane, the distance between the electrodes, the electrode surface area, or any combination thereof.

Assignees

• Us Gov Sec Navy

Inventors

• Dimascio Felice
• Willauer Heather D
• Hardy Dennis R
• Williams Frederick
• Lewis M Kathleen

Classifications

• C02F2201/46115

  Electrolytic cell with membranes or diaphragms · CPC title

• C01B32/50

  Carbon dioxide · CPC title

• C02F2001/46185

  only anodic or acidic water, e.g. for oxidizing or sterilizing · CPC title

• C25B1/00

  Electrolytic production of inorganic compounds or non-metals · CPC title

• C25B9/10

  Chemistry & Metallurgy · mapped topic