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The experiment was repeated without CaCO3 encasement of the anode (control experiment), with a maximum. pH of 8.35 being obtained, followed by a return to ...
Energy Procedia EnergyProcedia Procedia 00 1 (2009) Energy (2008)823–828 000–000 www.elsevier.com/locate/procedia www.elsevier.com/locate/XXX

GHGT-9

Electrochemical CO2 Capture and Storage With Hydrogen Genera tion Greg H. Rau a,b b

a Instiute of Marine Sciences, University of California, Santa Cruz, CA 95064, USA Carbon Management Program, Lawrence Livermore National Laboratory, Livermore, CA 954550 USA; [email protected]

Elsevier use only: Received date here; revised date here; accepted date here

Abstract Electrochemical splitting of calcium carbonate (e.g., as contained in inexpensive and abund ant minerals such as limestone) is proposed as a novel method of forming hydroxide solutions that can absorb, neutralize, and store carbon dioxide from the air or from waste streams. CaCO 3 is dissolved in the presence of the highly acidic anolyte of a saline water electrolysis cell, forming Ca(OH)2 and H 2CO 3 (or H 2O and CO 2). By maintaining a pH between 6 and 9 in the resulting solution, subsequent hydroxide reactions with CO 2 primarily produce dissolved calcium bicarbonate, Ca(HCO 3)2. Thus, for each mole of CaCO 3 split, there can be a net capture of up to 1 mole of CO 2. The resulting dissolved Ca(HCO 3)2 can be diluted and stored in the ocean, or in reservoirs on land or underground. Net process cost is estimated to be 2x10 6 TWh/yr [23]). Some small fraction of this en ergy could conceivably be converted to electricity and used to help electrochem ically stabilize or reduce atmospheric CO2 and/or to neutralize ocean acidity, and to add alkalinity to preserve marine calci fying organisms such as corals and shellfish. The a ctual cost, impact, safety, benefit, and practical scale of such a mitigation method remain to be demonstrated, however. Acknowledgments: Research supported in part by Grant 55043A/06 -26 from the Energy Innovations Small Grant Program of the California Energy Commission, and Grant B558132 from the Carbon Management Program, Lawrence Livermore National Laboratory.

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