Abstract: Six typical dynamic distillation models based on the published steady state models are established. The simulation of open - loop response of a depentanizer is used for comparison. The results show that the non- equilibrium effect and the inertia effect in an actual column are two important factors which can greatly influence the simulation of dynamic response process. Morever, the inertia effect seems to be more significant. Since both effects are considered in the proposed dynamic three - dimensional non - equilibrium mixing- pool model, it is believed to be most suitable to simulate the dynamic behavior of an industrial distillation column.