Equilibrium Data and Correlation with Redefined NRTL Equation of Aqueous Two-phase Systems Based on 1,4-Bis-(2-hydroxyethyl)-piperazine and Na₂SO₄

抄録

Aqueous two-phase system (ATPS) is considered a new method to remove heat stable salts (HSS) from flue gas desulfurizer 1,4-bis-(2-hydroxyethyl)-piperazine (BHEP). In this work, the liquid-liquid phase equilibrium data of BHEP-Na₂SO₄ ATPS in 303.15 – 323.15 K were measured and correlated by NRTL equation with the redefined adjustable characteristic constant at different concentrations. It is revealed that the redefined NRTL equation correlate to the phase equilibrium data of the ternary two-phase system well within the experimental temperature range. The root-mean-square deviations (RMSD) and the average absolute deviations (AAD) of the calculated value and experimental value are less than 1.9% and 1.5% respectively. The binary interaction parameters of NRTL equation have minor changes, ranging from -68 – 75. Thereby, the parameters of redefined NRTL equation are consistent with the actual calculation and engineering application requirements.