Analysis of Multi-loop Control Structures for Dividing-Wall Distillation Columns Using a Fundamental Model

Dividing-wall columns (DWCs) have significant potential as energy-efficient processes for the separation of multicomponent mixtures. However, in addition to an efficient steady state design, dynamics and control also play a major part for success of a technology. This is especially so for complex distillation systems.
This paper investigates the dynamics of a dividing wall column used for the separation of ternary mixtures. A detailed dynamic first principles-based model of the column is developed in gPROMS. The model is used to generate data used for control loop pairing via RGA, and controller parameters are found by using IMC tuning. The best control structures for DWC systems involving four different ternary mixtures, and two different feed compositions for each mixture, are investigated.