Semi‐Continuous <i>Ex Situ</i> Carbon Dioxide Mineralization in Produced Water for Calcite Production

<title>ABSTRACT</title> <p> The mineralization of carbon dioxide (CO ₂ ) to stable carbonate products is a desirable process for carbon capture utilization and storage (CCUS). However, improving the process economics through creative use of available reactants is necessary to develop a scalable mineralization process. This study details the development of a semi‐continuous CO ₂ mineralization process that uses flue gas as a point CO ₂ source, produced water (PW) as an alkaline source of Ca ²⁺ , and NaOH effluent (potentially sourced from integration with the chlor‐alkali process. Operating at a controlled pH allowed for both complete reaction of available Ca ²⁺ (100% carbonation potential or 9.9 g CO ₂ .L ^–1 PW brine) and for reproducible control of the produced calcium carbonate (CaCO ₃ ) product. A full factorial design of experiments was implemented to study the effects of reaction temperature, pH, and gaseous CO ₂ concentration on the mineralization and CO ₂ capture rates as well as product crystalline structure and morphology. A maximum CO ₂ capture rate of 0.315 ± 0.007 kg.L ^–1 .d ^–1 was achieved at 25°C and 25% CO ₂ . CO ₂ gas to liquid phase mass transport is believed to be the rate limiting step. With improved reactor design and optimization, the proposed semi‐continuous mineralization process shows promise for scaling to a pilot scale CO ₂ capture technology. </p>. Authors: Bennett, Quinn [Institute for Sustainable Energy &amp, the Environment Ohio University Athens Ohio USA]; Wolfe, Kody D. [Institute for Sustainable Energy &amp, the Environment Ohio University Athens Ohio USA] (ORCID:0000000264520107); Kasick, Andrew [Institute for Sustainable Energy &amp, the Environment Ohio University Athens Ohio USA, Department of Chemical and Biomolecular Engineering Ohio University Athens Ohio USA]; Shaffer, Reggie [Institute for Sustainable Energy &amp, the Environment Ohio University Athens Ohio USA]; Nyamekye, Edward [Institute for Sustainable Energy &amp, the Environment Ohio University Athens Ohio USA, Department of Chemical and Biomolecular Engineering Ohio University Athens Ohio USA]