Kinetics study and performance evaluation of a hybrid choline-glycine/ polyethylene glycol/water absorbent for CO2 separation

Thermodynamic and kinetic properties of absorbents are beneficial in evaluating their CO2 separation perfor-mance. In this study, the kinetic properties of CO2 in a hybrid choline-glycine/polyethylene glycol/water absorbent, including the liquid-side mass-transfer coefficient, enhancement factor, and reaction rate constant, were systematically determined through experimental measurements and data processing. Furthermore, an index referred to as absorbility was proposed to combine the kinetic properties determined in this study with the thermodynamic properties obtained in our previous study to evaluate the CO2 separation performance. Addi-tionally, the regeneration performance of the hybrid absorbent was also conducted. The results show that the performance of the hybrid absorbent (30 wt% [Cho][Gly] + 10 wt% PEG200 + 60 wt% H2O) is comparable to that of aqueous monoethanolamine, and is thus promising for CO2 separation, considering its low regeneration temperature and low environmental impact.

Automated summary

The kinetic properties of CO2 in a hybrid absorbent were determined, and an index called absorbility was proposed to evaluate the CO2 separation performance, combining the kinetic and thermodynamic properties. The results indicate that the hybrid absorbent performs comparably to traditional aqueous monoethanolamine, with the advantages of low regeneration temperature and low environmental impact.