Performance of a high capacity polyamine: Measurement and modeling of the solubility of carbon dioxide in aqueous solutions of 1, 4-bis (3-amino-propyl) piperazine and its heat of absorption

Abstract

This study focused on measuring the carbon dioxide (CO2) uptake capacity of an amine, 1, 4-Bis (3-aminopropyl) piperazine. The solubility of CO2 was measured at 313.15 K and 333.15 K for three amine concentrations (10, 20, and 30 wt%) of importance in industry and different CO2 partial pressures up to 2.4 MPa. CO2 loadings (mol of CO2/mol amine) were measured using the pressure decay method. At all concentrations, 1,4-Bis(3-aminopropyl) piperazine showed a higher CO2 loading compared to two benchmark amines namely, ethanolamine (MEA) and Piperazine (PZ). The proposed amine had also a higher capacity for CO2 than all other polyamines found in the literature, except, 3, 3 ’-Iminobis (N, N-dimethyl-propylamine) which has two tertiary and one secondary amino group. The experimental measurements were modeled comprehensively with the electrolyte–Non-Random Two Liquid (NRTL) model and the Redlich-Kwong (RK) equation of state (EOS) for the gas phase. The binary NRTL and molecule–ion pair parameters were regressed and reported. The overall percentage of the average absolute deviation (%AAD) between the experimental and estimated values for the temperature, pressure, and mole fractions were 0.12%, 0.07%, and 0.32%, respectively. Finally, the heats of absorption of CO2 in 1, 4-Bis (3-aminopropyl) piperazine were calculated using the Gibbs-Helmholtz equation based on the obtained experimental solubility data. The modeling results for MEA, DEA, and MDEA between the elec-NRTL and the soft-SAFT models were compared. The estimation of the heat of absorptions for the amines was almost the same.