Efficient Dynamic Phase Splitting Driven by Centrifugal Force for CO2 Capture from Flue Gas using Biphasic Solvents.

ABSTRACT

Carbon dioxide (CO2) chemisorption using biphasic solvents has been regarded as a promising approach, but challenges remain in achieving efficient dynamic phase-splitting during practical implementation. To address this, the centrifugal force was innovatively adopted to enhance the coalescence and separation of immiscible fine droplets within the biphasic solvent. The comprehensive evaluation demonstrates that centrifugal phase-splitting shows outstanding separation efficiency (>95%) and excellent applicability for various solvents. Correlation analysis reveals a strong relationship between the rich phase's viscosity, lean phase's residual CO2, and the phase separation efficiency. The time-profile behavior of immiscible droplets, observed through microscope images of phase-splitting, enables the estimation of the growth and coalescence rates of the discrete phase. Industrial-scale process simulation for technical and economic analysis confirms that the total capture cost ($ 42.5/t CO2) can be reduced by ∼22% with the use of biphasic solvents and a centrifugal separator compared to conventional methods. This study introduces a fresh perspective on polarity-induced cluster generation and coagulation-induced separation, offering an effective solution to address the challenges associated with dynamic phase-splitting in biphasic solvents during practical applications.