Method for extracting and sequestering carbon dioxide
AssigneeThe United States of America as represented by the United States Department of Energy
InventorsGregory H. Rau, Kenneth G. Caldeira
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Abstract
A method and apparatus to extract and sequester carbon dioxide (CO2) from a stream or volume of gas wherein said method and apparatus hydrates CO2, and reacts the resulting carbonic acid with carbonate. Suitable carbonates include, but are not limited to, carbonates of alkali metals and alkaline earth metals, preferably carbonates of calcium and magnesium. Waste products are metal cations and bicarbonate in solution or dehydrated metal salts, which when disposed of in a large body of water provide an effective way of sequestering CO2 from a gaseous environment.
Claims18
A method of extracting and sequestering CO2 from a gas stream, said method comprising the steps of:
- hydrating said CO2 in said gas stream with an aqueous solution to form carbonic acid, thereby resulting in a CO2-depleted gas stream;
- reacting said carbonic acid with carbonate to form a waste stream solution of metal ions and bicarbonate, wherein said carbonate is of the form X(CO3)m wherein X is any element or combination of elements that can chemically bond with a carbonate group or its multiple, wherein at least one said element is a group IA, IIA, IIIA, IVA, IB, IIB, IIIB, IVB, VB, VIB, VIIB, or VIIIB element of the periodic table, and
- wherein m is a stoichiometrically determined positive integer;
- pre-treating said waste stream solution to reduce the amount of CO2 outgassing and carbonate precipitation that may occur after said waste stream solution is released into a disposal site;
- and
- releasing said pre-treated waste stream solution into said disposal site, wherein said disposal site comprises a large body of water.
Dependencies are inferred from the claim text.