THE INFLUENCE OF DIFFERENT MODELS IN OBTAINING MULTIPLE SOLUTIONS IN DISTILLATION-COLUMNS

This paper is about the sensitivity of detection of multiple solutions to the structures or parameters incorporated in the equation system t hat represents a distillation column. The performance of different col umn simulation models, generally carried out in commercial simulators, is tested to detect multiplicity. The influence of the physicochemica l estimating methods and the adopted numeric strategies to solve disti llation problems is considered. Important behavioral differences have been found according to the model, the calculation method and the ther modynamic properties package used. Besides, the starting point is very important in the search of the hysteresis loop.