System and method for pressurized direct air capture of carbon dioxide

A high-pressure method for capturing dilute carbon dioxide directly from the atmosphere, comprising the following steps:

• a. filtering an atmospheric air stream comprising carbon dioxide to remove therefrom large debris, coarse dust, water droplets, mist, and very fine particulate matter, wherein such impurities are detrimental to a subsequent compressing step;
• b. compressing the atmospheric air stream comprising carbon dioxide to form a compressed atmospheric air stream, wherein the compressing step achieves a volume reduction of at least 98% as compared to the incoming atmospheric air stream, so as to enable a subsequent separating step to handle a volumetric capacity smaller than that of a subsequent separating step without said compressing step;
• c. introducing the compressed atmospheric air stream into a pressurized absorption zone;
• d. introducing a lean solvent stream into the pressurized absorption zone wherein the lean solvent stream comprises water and about 4 moles to about 6 moles of ammonia per liter of water, about 3 moles to about 5 moles of potassium carbonate per liter of water, and about 1 mole to about 3 moles of sodium carbonate per liter of water;
• e. operating the pressurized absorption zone at a pressure at a point in a range of about 50 bar to about 80 bar and a temperature at a point in a range of about 5° C. to about 60° C.;
• f. contacting the compressed atmospheric air stream with the lean solvent stream to absorb at least a portion of the carbon dioxide from the compressed atmospheric air stream;
• g. generating a rich solvent stream comprising the portion of the carbon dioxide and an air stream with reduced carbon dioxide content;
• h. introducing the rich solvent stream and the lean solvent stream into a pressure exchange zone;
• i. transferring pressure energy from the rich solvent stream to the lean solvent stream;
• j. introducing the rich solvent stream and the lean solvent stream into a heat exchange zone;
• k. thermally contacting the rich solvent stream with the lean solvent stream to transfer thermal energy from the lean solvent stream to the rich solvent stream;
• l. introducing the rich solvent stream into a stripping zone;
• m. operating the stripping zone at a pressure at a point in a range of about 1 bar to about 3 bar and a temperature at a point in a range of about 90° C. to about 140° C.;
• n. generating the lean solvent stream by removing at least a portion of carbon dioxide from the rich solvent stream;
• and
• o. expanding the air stream with reduced carbon dioxide content to recover mechanical power and at least partially compress the atmospheric air stream comprising carbon dioxide.

A high-pressure method for capturing dilute carbon dioxide directly from the atmosphere, comprising the following steps:

• a. filtering an atmospheric air stream comprising carbon dioxide to remove therefrom large debris, coarse dust, water droplets, mist, and very fine particulate matter, wherein such impurities are detrimental to a subsequent compressing step;
• b. compressing the atmospheric air stream comprising carbon dioxide to form a compressed atmospheric air stream, wherein the compressing step achieves a volume reduction of at least 98% as compared to the incoming atmospheric air stream, so as to enable a subsequent separating step to handle a volumetric capacity smaller than that of a subsequent separating step without said compressing step;
• c. introducing the compressed atmospheric air stream into a gas membrane zone;
• d. operating the gas membrane zone at a pressure at a point in a range of about 50 bar to about 300 bar, and at a temperature at a point in a range of about ambient temperature to about 150° C.
• e. separating at least a portion of the carbon dioxide from the compressed atmospheric air stream;
• f. generating a carbon dioxide rich stream and an air stream with reduced carbon dioxide content.
• g. introducing the compressed atmospheric air stream and the air stream with reduced carbon dioxide content into a heat exchange zone;
• h. thermally contacting the compressed atmospheric air stream with the air stream with reduced carbon dioxide content;
• i. transferring thermal energy from the compressed atmospheric air stream to the air stream with reduced carbon dioxide content.
• j. introducing the air stream with reduced carbon dioxide content into an expansion zone;
• k. expanding the air stream with reduced carbon dioxide content to generate mechanical power, and
• l. recovering the mechanical power generated to at least partially compress the atmospheric air stream comprising carbon dioxide.