Estudo do equilíbrio líquido-vapor pela formulação Phi-Phi : procedimento para correção do parâmetro de interação binária kij

Abstract

The calculation of liquid-vapor equilibrium plays a central role in thermodynamics and process simulations, as its use is necessary in single-stage flash calculations, distillation columns, compressors, pumps, mixers, and valves. However, solving the equation is challenging in non-ideal systems. The Phi-Phi formulation offers greater simplicity with respect to its modeling, as well as in obtaining the parameters necessary for its resolution. However, it has limitations in representing deviations in the liquid phase. This study develops a procedure to correct the Phi-Phi formulation by performing regression of the binary interaction parameter kij using data obtained from the Gamma-Phi formulation, thereby expanding its applicability to mixtures with non-ideal liquid phases. To achieve this, Phi-Phi and Gamma-Phi formulations were implemented in MATLAB®, using the Soave-Redlich-Kwong (SRK) and Peng-Robinson (PR) equations of state, as well as the activity models of Non-Random Two Liquids (NRTL) and UNIFAC. To ensure that the proposed procedure functions correctly, ten systems were analyzed. The results obtained for the studied mixtures were satisfactory based on validation with experimental data.