<![CDATA[Liquid–liquid extraction (LLE) is a critical separation process in industrial applications, often limited by solvent losses and environmental concerns. This study presents the development and optimization of a closed-loop LLE system incorporating solvent recovery, aimed at reducing total annualized cost (TAC), solvent make-up, and CO₂ emissions. Thermodynamic modeling using NRTL and UNIQUAC was validated against experimental tie-line data to ensure accurate simulation of phase behavior. Solvent screening was conducted based on distribution coefficient, selectivity, viscosity, and safety metrics. Aspen Plus simulations modeled a multistage extractor and integrated distillation unit, followed by optimization of solvent-to-feed ratio, number of stages, and recovery conditions. The optimized closed-loop system achieved a 30% reduction in TAC, over 60% reduction in solvent make-up, and a 35% decrease in CO₂ proxy emissions compared to an open-loop benchmark. Rate-based modeling enhanced simulation fidelity, and economic and environmental metrics confirmed the sustainability of the proposed configuration. These results demonstrate the effectiveness of combining solvent recovery and process simulation to improve the sustainability and economic performance of LLE operations.]]>
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