Cyclic CO2 absorption capacity of aqueous single and blended amine solvents

The cyclic CO2 absorption capacity (cyclic capacity) of aqueous single and blended amines was systematically analyzed for imaginary as well as real amines using thermodynamic models. The Kent-Eisenberg model and Henry's law were employed to design the single imaginary amines. The protonation constant (pK(a)) and carbamate stability constant (K-c) were varied over a wide range to cover the main characteristics of existing monoamines applicable for CO2 capture, and the effects of the pK(a), K-c, and amine concentration on the cyclic capacity were carefully investigated. Binary imaginary amine blends were designed by mixing an amine with low carbamate preference with one able to generate carbamates. In addition, an analogous investigation was conducted by considering the effect of the blending ratio of binary blends of four real monoamines (methyldiethanolamine, monoethanolamine, diethanolamine, and aminomethylpropanol) to demonstrate the practicality of this approach. Finally, the cyclic capacity of piperazine (diamine) and its binary blends with the four real monoamines was investigated. (C) 2018 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.