Techno-economic feasibility and sensitivity analysis of aqueous ionic liquid-amine hybrid solvents-based CO2 chemical capture processes

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Ionic liquids (ILs) and amines are among the most effective chemical absorbents for CO₂ capture; their combination in hybrid systems enables synergistic interactions that improve absorption efficiency, kinetics, and thermal stability. This study investigates the high-pressure CO₂ absorption and diffusion kinetics of aqueous ionic liquid-amine hybrid (ILAH) solvents composed of 1-butyl-3-methylimidazolium acetate ([BMIM][AC]), N-methyl diethanolamine (MDEA), and piperazine (PZ). Using a Design of Experiments (DOE) approach, the effects of IL concentration, temperature, and pressure on CO₂ solubility, capture efficiency, and overall mass transfer rates were systematically analyzed. Experimental data investigated over 2-50 bar and 303.15-333.15 K revealed a maximum CO₂ solubility of 2.182 mol CO₂ mol⁻¹ solvent at 25 °C, outperforming conventional amine-based systems. The validated thermodynamic and kinetic model reproduced experimental CO₂ loadings with high conformity across the studied conditions, confirming the suitability of the implemented mass transfer correlations for process simulation. Subsequent techno-economic analysis calculated the influence of key operational variables on CO2 capture performance and cost metrics. The specific CO₂ capture cost ranged from 78.03 to 125 USD t⁻¹ CO₂, depending on IL concentration, operating pressure, and absorption temperature. The sensitivity analysis identified operating expenditure and captured CO₂ throughput as the principal cost drivers, while financial assumptions and capital exhibited marginal effects. Overall, the integration of high-pressure experimental data, model validation, and techno-economic evaluation establishes a comprehensive framework for developing energy-efficient and economically viable CO₂ capture processes using aqueous ILAH solvents. These results establish the strong potential of [BMIM][AC]-MDEA-PZ systems as next-generation absorbents for industrial carbon capture under high-pressure conditions.