Efficient dynamic model for batch distillation

A novel, rigorous and efficient solution technique for multicomponent batch distillation modelling equations is proposed. Model predictions using the technique are shown to be in close agreement with experimental batch distillation data for a ten sieve tray, 15 cm diameter column separating ethanol and water. The results also show improved accuracy over commercially available programs for batch distillation. The method incorporates rigorous dynamic energy balances as well as accurate representation of both tray hydraulics and non-ideal mass transfer. The technique is based on a functional approximation for liquid enthalpy and makes a difficult-to-calculate temperature derivative implicit in other terms in the equations, eliminating the need for iterative solution techniques. The numerical efficiency of the method permits its utilization in model-based optimization and control calculations. The modelling approach is applicable to both batch and continuous dynamic distillation models.