Simulation and Optimization of Chemical Process using GAMS Mix Pattern

Rigorous simulation and optimization of chemical process systems usually is based on a realistic calculation of the physical properties. Within GAMS models, nonlinear functions for the realistic calculation leads to very complex models and greatly increased dimensions. By using the new mechanism, a mix pattern with external functions, the situation can be improved by transferring calculation procedures to an external module. In this work, the external functions, written in the programming language Fortran, are used for the physical properties calculation in the flash process of a distillation column. The accuracy of the result is comparable to standard simulation software