Systems and methods for direct air carbon dioxide capture
A method for capturing and sequestering carbon dioxide (CO 2 ) includes receiving and performing an electrochemical process on the input liquid including water and a salt to produce at least one hydroxide-rich stream, and then capturing CO 2 from air using the hydroxide-rich stream and a passive air capture system, thereby producing a liquid carbonate solution containing air-captured CO 2 . Optional steps include disposing of the liquid carbonate solution, precipitating air-captured CO 2 from the liquid carbonate solution as solid carbonate and/or a slurry of carbonate, and mixing the liquid carbonate solution with a hydrogen-rich stream produced by the electrochemical process to generate gaseous CO 2 . Various integrations and synergies among CO 2 capture, renewable energy, water desalination, and metal and mineral extraction are provided.
1. A method for capturing and sequestering carbon dioxide (CO 2 ), comprising:
receiving an input liquid comprising at least one of seawater, brackish water, and brine effluent;
performing an electrochemical process on the input liquid to produce at least one hydroxide-rich stream;
capturing CO 2 from air using the hydroxide-rich stream and a passive direct air capture system, thereby producing a liquid carbonate solution;
precipitating a solid carbonate and/or a slurry of carbonate from the liquid carbonate solution;
producing a hydrogen-rich stream at least in part with the electrochemical process;
dissolving a metal and/or a mineral into the hydrogen-rich stream to produce a metal and/or a mineral solution;
mixing the solid carbonate and/or the slurry of carbonate from the liquid carbonate solution with the metal and/or the mineral solution to produce a metal and/or a mineral carbonate mixture;
precipitating a metal and/or a mineral carbonate from the metal and/or the mineral carbonate mixture; and
recycling a salt solution from the metal and/or the mineral carbonate mixture by mixing the salt solution with the input liquid upstream from the electrochemical process.
2. The method of claim 1 , further comprising pretreating the input liquid with the solid carbonate and/or the slurry of carbonate from the liquid carbonate solution.
3. The method of claim 1 , further comprising processing the input liquid with a pretreatment stage before performing the electrochemical process, the pretreatment stage comprising one or more of a filtration system, a reverse osmosis concentration system, and an ion exchange system.
4. The method of claim 1 , wherein performing the electrochemical process comprises performing electrodialysis with a bipolar membrane electrodialysis unit constructed and arranged to produce the at least one hydroxide-rich stream, the hydrogen-rich stream, and hydrogen gas.
5. The method of claim 1 , wherein performing the electrochemical process comprises performing electrolysis to produce the at least one hydroxide-rich stream, hydrogen gas, and chlorine gas.
6. The method of claim 5 , wherein producing the hydrogen-rich stream comprises combining the hydrogen gas and the chlorine gas to produce hydrochloric acid.
7. The method of claim 1 , wherein the brine effluent comprises a desalination waste brine from a desalination facility.