Advancing the large-scale development of PCC processes by providing essential VLE data for aqueous solutions of amines

Abstract

New vapor liquid equilibrium (VLE) ebulliometric data is provided for ternary aqueous 2-Amino-2-methyl-1-propanol (AMP) and Piperazine (PZ) solutions for a range of temperatures (30 ºC, 40 ºC and 50 ºC) and different AMP/PZ ratios (3:1.5 / 4:1 / 6:1). The selected conditions and concentrations are representative of those expected in the water wash systems, typically located at the top of an absorption column. The NRTL thermodynamic model in Aspen Plus is used to correlate the VLE data and determine new AMP/PZ binary interaction parameters, leading to an improvement on the prediction of the amine volatility. The scatter in the experimental data for the AMP and PZ concentrations in the vapor phase, however, suggests that VLE data are subjected to substantial uncertainty at low temperatures and low amine concentrations. Experimental VLE data show a small interaction between amine molecules since an increase in the AMP/PZ ratio, for a given AMP and PZ concentration and temperature, does not have a significant effect on either AMP or PZ volatilities.

Keywords: CO2 capture, absorption, second generation solvents, vapor liquid equilibria, NRTL model, amine volatility