Mass Transfer Kinetics and Thermodynamics Evaluation of 1-Amino-2-propanol/Sulfolane Biphasic Solution for CO2 Absorption

Abstract

The utilization of biphasic absorbents for CO₂ capture can substantially reduce energy consumption. This study investigated the mass transfer kinetics and thermodynamics of the phase separation absorption process using 1-amino-2-propanol (MIPA)/sulfolane (TMS) biphasic solvents. ¹³C NMR spectroscopy was employed to analyze the species in different CO₂-loaded solutions. The direction and extent of species transfer during the absorption process were elucidated and the phase separation mechanism was explored. CO₂ absorption kinetics were studied in a wetted-wall column, and the physicochemical properties and the absorption reaction kinetics data under different experimental conditions were obtained. Results showed the overall mass transfer coefficient (K_G) was 1.6 times higher than 30 wt % MEA and twice that of DETA/TMS solution. NMR and kinetic data analysis revealed that phase separation is mainly contributing to the deterioration of the mass transfer process in biphasic solution, reducing the liquid-film mass transfer coefficient (K_L) by 63.2% during the phase separation stage. Furthermore, the desorption heats of different biphasic solvents with identical amine concentrations were measured using a microcalorimeter. Findings indicated that TMS did not alter the thermodynamic properties of the solution. Since only the CO₂-rich phase is regenerated, the energy consumption is significantly reduced compared to that of MEA.