Modeling the phase equilibria of the HIx mixture using the SAFT-VRE equation of state: Binary systems

Abstract The design and optimization of the separation units of the sulfur-iodine (SI) cycle process for hydrogen production requires a comprehensive analysis of the phase behavior of complex electrolyte solutions. Here, we apply the SAFT-VRE equation of state for electrolyte solutions to represent the phase equilibria of the HIx mixture (HI + H 2 O + I 2 ) encountered in the reactive distillation column of the SI process. The phase equilibria of the binary mixtures (I 2  + H 2 O, HI + I 2 and H 2 O + HI) are accurately represented with the SAFT-VRE model. One key advantage of the SAFT-VRE model is the possibility to predict phase equilibria at high pressures and the densities of the coexistent phases, as well as the mean activity and osmotic coefficients of HI.