Potential of a 1-Amino-2-Propanol/Sulfolane Biphasic Solution for CO₂ Capture: Performance and Mechanism Study

Abstract

In order to reduce the regeneration energy consumption of CO 2 capture in the postcombustion capture process and explore the regulatory characteristics of phase separation, a series of 1-amino-2-propanol (MIPA)/sulfolane biphasic solutions were proposed to capture CO 2 . The effects of the molar ratio on the phase separation behavior, CO 2 equilibrium absorption, and desorption performances of MIPA/solfolane biphasic absorbents as well as three ternary solutions with the extra addition of ethanolamine (MEA) were investigated comprehensively in experiments. The results showed that the 4M/5M MIPA/sulfolane biphasic solution exhibited excellent performance with higher CO 2 loadings in the phase separation point for a CO 2 -rich liquid (0.4530 mol/mol), better desorption efficiency (85.53%), and relatively low regeneration energy consumption (32% lower than 30 wt % MEA). Besides, MEA has a positive effect on promoting the phase separation of the MIPA/sulfolane solution and reducing the desorption energy consumption. Furthermore, 1 H and 13 C nuclear magnetic resonance (NMR) spectroscopy was used to explore the reaction and phase separation mechanisms. The results indicated that generated carbamate salts can increase the ionic strength of the aqueous solution, leading to the accumulation of reacted MIPA or MEA in the water phase and the exclusion of sulfolane from water to form a new liquid phase. The results of this work can provide theoretical support for the future industrial application of MIPA/sulfolane biphasic absorbents and offer some guidance for the mechanism exploration of other biphasic solvent systems.