Energy-efficient CO2 capture using potassium prolinate/ethanol solution as a phase-changing absorbent

High energy consumption for aqueous amine-based CO2 capture process is still a major drawback limiting its commercial deployment. Most of heat is used for water vaporization during solvent regeneration for CO2 stripping. Development of phase-changing solvents is an attractive energy-efficient method to reduce energy requirement. In this work, we have proposed potassium prolinate (ProK)/ethanol solution as a novel non-aqueous absorbent. Its physical properties and the rate of CO2 absorption were investigated and compared with the aqueous ProK systems. Phase behaviours during CO2 absorption and partition of CO2 absorbed between liquid and solid phases were characterized. The main species in solid precipitates were identified as bicarbonate and proline salts by 13C NMR and XRD. Moreover, the regenerated absorbents can remain relatively stable after absorption-desorption cycles.