Modeling of Simultaneous Chemical and Phase Equilibria in Systems Involving Non-reactive and Reactive Azeotropes

Simultaneous chemical and phase equilibrium (CPE) calculations are essential in chemical engineering, finding numerous applications in industrial processes, such as reactive distillation. CPE calculations can be challenging in systems involving polar and associating components, which also exhibit azeotropes or even reactive azeotropes, with two common examples being methyl tert-butyl ether and isopropyl acetate synthesis systems. To tackle the problem, a robust algorithm for solving CPE is required, coupled with an accurate thermodynamic model for describing system nonideality. In this work, a Gibbs energy minimization algorithm based on the method of Lagrange multipliers is employed for performing CPE calculations in the aforementioned systems. The algorithm is coupled with traditional activity coefficient models UNIQUAC and UNIFAC, as well as the UMR-PRU model. The results indicate that all models can successfully describe the CPE in the studied systems. UMR-PRU yields very satisfactory results, despite being utilized as a purely predictive tool.