Potential for the Simultaneous Capture and Utilization of CO2 Using Desalination Reject Brine: Amine Solvent Selection and Evaluation

Abstract

In the present study, the potential for the use of different amines with desalination brines for the simultaneous capture and conversion of CO2 into solid bicarbonates was evaluated. The focus of this work was to find the most suitable amine solvent for this proposed process. Various classes of amine solvents such as primary, secondary, tertiary and cyclic amines were identified and evaluated using the following parameters: Precipitate yield, CO2 capacity and Sodium conversion. The results showed that bicarbonate salts of good purity can be synthesized by bubbling simulated flue gas into amine/brine solution. Also the sterically hindered amine, AMP, was found to be the best amine for the process due to its high precipitate yield and sodium conversion. Sodium removal above 80% was obtained when AMP was used. For all amines tested, the precipitated bicarbonate had a purity of over 95% while the CO2 capacity varied, with Piperazine having the highest. The obtained results demonstrate that the proposed process is a promising technology for the simultaneous capture and utilization of CO2 using desalination reject brine.