Thermochemical model for evaluating CO2 regeneration energy for amine absorbents

We present a thermochemical model for evaluating CO2 regeneration energies for aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), 2-amino-2-methyl-1-propanol (AMP), and 2-(isopropylamino)ethanol (IPAE). The regeneration heat consists of the reaction heat, the sensible heat, and the vaporization heat. We calculated the reaction heat using a thermochemical model. We calculated the concentrations of all chemical species present in the CO2 absorption state at 40 degrees C and the CO2 release state at 120 degrees C. We calculated the reaction heat by summing enthalpies of associated reactions and reacted molar quantities derived from the concentration changes between the absorption and release states. For sterically hindered amines AMP and IPAE, the contribution of the protonation reaction to the reaction heat is large, whereas the contributions of protonation and carbamate hydrolysis are large for MEA and DEA. In the regeneration heat, the sensible heat is much larger than the reaction and vapor-ization heats.(c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

We developed a thermochemical model to evaluate the CO2 regeneration energies in aqueous solutions of MEA, DEA, AMP, and IPAE. The regeneration heat includes reaction heat, sensible heat, and vaporization heat. We calculated the reaction heat using our model and determined the concentrations of all chemical species in the CO2 absorption and release states. The contribution of protonation reaction is significant in sterically hindered amines AMP and IPAE, while both protonation and carbamate hydrolysis play important roles in MEA and DEA. Sensible heat dominates the regeneration heat compared to reaction and vaporization heats.