Philippe expresses that distillation columns operating in batch mode are very complex to model mainly due to the dynamic nature of the operation. This dynamic nature is enhanced by the possible discontinuities that must be correctly handled by the Process Modelling Environment. Furthermore, when using an external Property Package, the simulation success is directly linked to the quality of the Property Package as well as the availability of the various properties required and their derivatives with respect to the operating variables (temperature, pressure, and mole numbers).
The talk illustrates the use of a CAPE-OPEN Property Package into a commercial software dedicated to the simulation of batch distillation columns through the thermodynamic socket feature, using CAPE-OPEN thermodynamic specification 1.0 and 1.1. The property package is provided by COCO-TEA from AmsterChem and the Process Modelling Environment is BatchColumn from ProSim SA. The system to be separated is a mixture containing water, toluene, acetonitrile and methanol.
Philippe focuses on numerical aspects and particularly on the need for the PME to be able to access to accurate derivatives of the equilibrium properties like K-values. A comparison with the native thermodynamic server (Simulis Thermodynamics) is presented and the modifications required to improve the chances for a successful simulation when using a CAPE-OPEN package are detailed.