Experiment and modeling solubility of CO2 in aqueous solutions of Diisopropanolamine + 2-amino-2-methyl-1-propanol + Piperazine at high pressures

Abstract

Removal of acid gases from natural and flue gases is vital in gas treatment processes. Using a high pressure cell, the (vapor+liquid) equilibrium data for solubility of CO2 in the aqueous mixtures of diisopropanolamine (DIPA)+2-amino-2-methyl-1-propanol (AMP)+piperazine (PZ) are obtained at 313.15, 328.15 and 343.15K and pressure range of 1–40bar. Also the experimental measurements for solubility of CO2 in the aqueous (DIPA+AMP) -(DIPA+PZ) systems and the binary aqueous DIPA system are carried out at the same conditions as above. The compositions of the quaternary aqueous mixtures are: (36wt.% DIPA+7wt.% AMP+2wt.% PZ), (30wt.% DIPA+10wt.% AMP+5 wt% PZ), (24wt.% DIPA+13wt.% AMP+8wt.% PZ), for the ternary mixtures are: (24wt.% DIPA+21 wt% AMP), (24wt.% DIPA+21wt.% PZ) and for the binary mixture is 45wt.% DIPA, keeping the total aqueous amine concentration at 45wt.%. The results are presented as the partial pressure of CO2 against acid gas loading (mol CO2/mol total amine). It’s observed that using the AMP-PZ blend as an activator for the DIPA solution increases the CO2 loading so that the absorption of CO2 enhances in the aqueous DIPA solution. Moreover, the Electrolyte-NRTL model is used to model the experimental data of this work and the other aqueous alkalonamine+acid gas mixtures from the literature data.The percent of the average absolute deviation, AAD%, between the calculated partial pressure of CO2 and experiment is 20.3 for the quaternary aqueous-alkanolamines mixtures.