Operation of a packed distillation column: Modelling and experiments

A nonequilibrium model for the dynamic simulation of packed distillation columns is illustrated in this paper. The nonequilibrium model includes the direct calculation of the rates of mass and energy transfer between vapour and liquid phases. It is better able to model the actual physical processes occurring in a real distillation column than is the conventional equilibrium stage model so often used for these calculations. In order to test the model described above we have carried out experiments in a pilot scale column at the University of Dortmund. The column has a diameter of 0.1 m and is equipped with Rombopak 6M structured packing. Extractive distillation experiments were carried out with acetone-methanol-water under atmospheric pressure with specified reflux ratio and reboiler heat duty. This system was chosen because of its nonideality, therefore, it provides a more stringent test of the nonequilibrium model than would a thermodynamically ideal mixture. The dynamic nonequilibrium model appears to be able to predict the performance of the experimental column quite well.