IP Library Granted Patent US 12698695
Granted Patent B2
US 12698695 · App. 18/919,246 · Granted Aug 4, 2026

Systems and methods for sequestering alkaline carbonates with captured CO

Inventors: Luke Shors (Rotorua, NZ); Jeanine Ash (Seattle, WA); Alishan Salim (Spring, TX); David Sheh (Oakland, CA); Rahul Surana (Fremont, CA)
Assignee: Capture6 Corp
E21B41/0064Y02C20/40
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Quick Facts
Patent No.
US 12698695
App. No.
18/919,246
Granted
Aug 4, 2026
Kind
B2
Abstract

A method for sequestering carbon dioxide (CO 2 ) includes receiving an alkaline fluid stream and receiving an acidic stream. The alkaline fluid stream and the acidic stream are produced by a direct air carbon capture process and the carbonate includes air-captured CO 2 . The method also includes producing a pH balanced CO 2 stream by mixing the alkaline fluid stream with an acidic mixing portion comprising 0% up to 100% of the acidic stream, and storing the pH balanced CO 2 stream in a storage location. The storage location can include at least one of a subsurface location, on land, or in a water body. The storage location and the pH balanced CO 2 stream are configured to provide long-term storage of the air-captured CO 2 .

Claims (28)

1 . A method for sequestering carbon dioxide (CO 2 ), comprising:

receiving an alkaline fluid stream comprising carbonate produced by a direct air carbon capture process, the carbonate comprising air-captured CO 2 ,

wherein the direct air carbon capture process comprises using an electrochemical process to produce a hydroxide-rich stream from an input liquid and to produce an acidic stream, and using the hydroxide-rich stream to capture CO 2 from air, thus producing the alkaline fluid stream comprising the carbonate;

receiving the acidic stream produced by the direct air carbon capture process;

producing a pH balanced CO 2 stream comprising mixing the alkaline fluid stream with an acidic mixing portion comprising 0% up to 100% of the acidic stream by alternately injecting the alkaline fluid stream and the acidic mixing portion into a subsurface location; and

storing the pH balanced CO 2 stream in a storage location comprising the subsurface location;

wherein the storage location and the pH balanced CO 2 stream provide long-term storage of the air-captured CO 2 comprising sequestration of the air-captured CO 2 for a time period ranging from decades to thousands of years.

2 . The method of claim 1 , further comprising alternately injecting the alkaline fluid stream and the acidic mixing portion thereby increasing carbonation of mineral rock to expand a mineralization area.

3 . The method of claim 1 , further comprising injecting the alkaline fluid stream and the acidic mixing portion into a subsurface mafic or ultramafic formation.

4 . The method of claim 1 , further comprising mixing the acidic stream with an alkaline material before mixing the alkaline fluid stream with the acidic mixing portion.

5 . The method of claim 4 , wherein the alkaline material comprises mafic or ultramafic rocks.

6 . The method of claim 4 , wherein the alkaline material comprises olivine.

7 . The method of claim 4 , wherein the alkaline material comprises sedimentary material.

8 . The method of claim 1 , wherein alternately injecting the alkaline fluid stream and the acidic mixing portion comprises a repeating loop comprising first injecting the acidic mixing portion and then injecting the alkaline fluid stream.

9 . The method of claim 1 , wherein the storage location comprises a sedimentary basin.

10 . The method of claim 9 , wherein the sedimentary basin comprises a saline aquifer.

11 . The method of claim 9 , wherein the sedimentary basin comprises a depleted oil reservoir.

12 . The method of claim 1 , further comprising dissolving additional CO 2 in the alkaline fluid stream to form alkaline bicarbonates.

13 . A method for sequestering carbon dioxide (CO 2 ), comprising:

receiving an alkaline fluid stream comprising carbonate produced by a direct air carbon capture process, the carbonate comprising air-captured CO 2 ,

wherein the direct air carbon capture process comprises using an electrochemical process to produce a hydroxide-rich stream from an input liquid and to produce an acidic stream, and using the hydroxide-rich stream to capture CO 2 from air, thus producing the alkaline fluid stream comprising the carbonate;

receiving an acidic stream produced by the direct air carbon capture process;

producing a pH balanced CO 2 stream by mixing the alkaline fluid stream with an acidic mixing portion comprising 0% up to 100% of the acidic stream;

injecting the alkaline fluid stream and the acidic mixing portion into a subsurface storage location comprising a mafic or ultramafic formation; and

simultaneously injecting the alkaline fluid stream and the acidic mixing portion at a fluid pressure to create seltzer at the subsurface storage location of the injection or during the injection,

wherein the subsurface storage location and the pH balanced CO 2 stream provide long-term storage of the air-captured CO 2 comprising sequestration of the air-captured CO 2 for a time period ranging from decades to thousands of years.

14 . The method of claim 13 , further comprising dissolving an alkaline material in the acidic stream prior to mixing the alkaline fluid stream with the acidic mixing portion.

15 . The method of claim 13 , further comprising mixing olivine with the acidic stream to produce an alkaline chloride solution and mixing the alkaline chloride solution with the alkaline fluid stream.