Energy efficient method for stripping CO2 from seawater

• US 9,914,644 B1
• Filed: 06/11/2015
• Issued: 03/13/2018
• Est. Priority Date: 06/11/2015
• Status: Active Grant

• Current Assignee: X Development LLC (Alphabet Inc.)
• Original Assignee: X Development LLC (Alphabet Inc.)
• Inventors: Eisaman, Matthew
• Primary Examiner(s): McCracken, Daniel C
• Application Number:
  US14/736,847
• Time in Patent Office: 1,006 Days
• Field of Search: 423438
• CPC Class Codes: B01D 19/0036 Flash degasification the other groups take precedence
• CPC Class Codes: B01D 19/0063 Regulation, control including valves and floats for construction and details of valves F16K
• CPC Class Codes: B01D 19/0068 General arrangements, e.g. flowsheets B01D19/0063 takes precedence
• CPC Class Codes: B01D 19/0084 using an electric current
• CPC Class Codes: B01D 19/04 by addition of chemical substances
• CPC Class Codes: B01D 2311/04 Specific process operations in the feed stream; Feed pretreatment
• CPC Class Codes: B01D 2311/103 Heating
• CPC Class Codes: B01D 2311/106 Cooling
• CPC Class Codes: B01D 2313/36 Energy sources
• CPC Class Codes: B01D 2313/367 Renewable energy sources, e.g. wind or solar sources
• CPC Class Codes: B01D 61/422 Electrodialysis
• CPC Class Codes: B01D 61/445 with bipolar membranes; Water splitting
• CPC Class Codes: C01B 32/50 Carbon dioxide
• CPC Class Codes: C02F 1/20 by degassing, i.e. liberation of dissolved gases degasification of liquids in general B01D19/00; arrangement of degassing apparatus in boiler feed supply F22D
• CPC Class Codes: C02F 1/4693 electrodialysis
• CPC Class Codes: C02F 2101/10 Inorganic compounds
• CPC Class Codes: C02F 2103/08 Seawater, e.g. for desalination
• CPC Class Codes: C02F 2201/46 Apparatus for electrochemical processes

Abstract

A method including increasing modifying a volume of seawater that holds an amount of dissolved inorganic carbon; acidifying the amount of seawater; and collecting an amount of carbon dioxide from the acidified seawater. A system including an electrodialysis unit including an acidified solution compartment, a basified solution compartment, a membrane and an acidified solution output compartment; a vessel coupled to an inlet of the acidified solution compartment and operable to contain a modified volume of seawater therein; and a desorption unit coupled to the acidified compartment output, the desorption unit operable to receive carbon dioxide gas from a solution from the acidified output compartment.

Claims

1. A method comprising:

increasing a concentration of dissolved inorganic carbon in a volume of seawater to produce modified seawater;

acidifying the modified seawater by flowing the modified seawater into an acidified solution compartment in an electrodialysis unit;

flowing the seawater from a second volume of the seawater into a basified solution compartment in the electrodialysis unit at the same time as flowing the modified seawater into the acidified solution compartment, wherein the second volume of the seawater is unmodified; and

collecting an amount of carbon dioxide from the acidified seawater.

2. The method of claim 1, wherein increasing a concentration of dissolved inorganic carbon in the seawater comprises heating the seawater.

3. The method of claim 2, wherein heating the seawater comprises exposing the seawater to low grade heat.

4. The method of claim 2, wherein heating the seawater comprises exposing the seawater to solar thermal energy.

5. The method of claim 1, wherein prior to acidifying the modified seawater, the method comprises cooling the modified seawater.

6. The method of claim 1, wherein after acidifying the modified seawater, the method comprises transferring the acidified seawater to a tank, and collecting an amount of carbon dioxide from the acidified seawater comprises collecting the carbon dioxide that escapes from the acidified seawater in the tank.

7. The method of claim 5, wherein prior to transferring the acidified seawater to the tank, the method comprises evacuating the tank of air.

8. The method of claim 1, wherein collecting an amount of carbon dioxide comprises vacuum stripping the carbon dioxide from the acidified seawater.

9. A method comprising:

removing a portion of water molecules from a volume of seawater comprising an amount of dissolved inorganic carbon to form modified seawater;

after removing a portion of water molecules from the volume of seawater, introducing the modified seawater into an acidified solution compartment in an electrodialysis unit;

acidifying the seawater in the acidified solution compartment;

at the same time as introducing the modified seawater into the acidified solution compartment, introducing the seawater from a second volume of the seawater into a basified solution compartment in the electrodialysis unit, wherein the second volume of the seawater is unmodified; and

collecting an amount of carbon dioxide from the acidified seawater.

10. The method of claim 9, wherein removing a portion of water molecules from a volume of seawater comprises heating the seawater.

11. The method of claim 10, wherein heating the seawater comprises exposing the seawater to low grade heat.

12. The method of claim 10, wherein heating the seawater comprises exposing the seawater to solar thermal energy.

13. The method of claim 10, wherein prior to introducing the seawater into an electrodialysis unit, the method comprises cooling the modified seawater.

14. The method of claim 9, wherein after acidifying the modified seawater, the method comprises transferring the acidified seawater to a tank, and collecting an amount of carbon dioxide from the acidified seawater comprises collecting the carbon dioxide that escapes from the acidified seawater in the tank.

15. The method of claim 14, wherein prior to transferring the acidified seawater to the tank, the method comprises evacuating the tank of air.

16. The method of claim 9, wherein collecting an amount of carbon dioxide comprises vacuum stripping the carbon dioxide from the acidified seawater.