MSF Desalination Process Simulation using electrolyte-NRTL model

Abstract

Conventional modeling of MSF desalination plants relies on empirical correlations to estimate seawater thermodynamic properties. However, since MSF units operate through multiple liquid–vapor equilibrium stages, an accurate representation of the working fluid is essential. This study applies an alternative approach based on the electrolyte Non-Random Two-Liquid (eNRTL) model, considering seawater as an aqueous ionic solution (Na⁺, Mg²⁺, Ca²⁺, Cl^-, SO₄^2-, among others) and incorporating activity coefficients to describe phase behavior. The model, previously validated against experimental data over a wide range of compositions and temperatures, was applied here to simulate the Al Khobar II MSF plant, with errors under 3 %. The proposed approach is not restricted by concentration, temperature, or pressure; offering a robust alternative for the physicochemical representation of seawater in desalination process optimization.