Evaluation of Dynamic Models of Distillation Columns with Emphasis on the Initial Response

The flow dynamics (tray hydraulics) are of key importance for the initial dynamic response of distillation columns. The most important parameters are the liquid holdup, the liquid hydraulic time constant and the vapor constant representing the initial effect of a change in vapor flow on liquid flow. In the paper we present methods for determining these parameters experimentally, and compare the results with estimates from available correlations such as the Francis Weir formula

Reduced models and control of distillation columns with sharp temperature profiles

Distillation columns with sharp temperature profiles exhibit a characteristic dynamic behaviour which is used in this correspondence to deduce a consiederably implified low-order dynamic model. Based on this model, linear state-space methods are employed in the design of the control of an extractive distillation column with a vapor side stream. (5 References