Dynamic behaviour and control of extended Petlyuk distillation arrangements

Thermal coupling of heat and mass leads to complex configurations and difficult control problems. We study here the dynamic behavior of a high purity, 4-product extended Petlyuk column with nominal operating point close to the analytic minimum energy for sharp seperation and propose and four different decentralized control structures. We subject the different control structures to wide range of disturbances and propose robust control structures that can handle them while remaining close to the minimum energy for the given purity specification. Another aspect of this work is the use of V-min diagrams which can predict a worst case disturbance and can reason out the failure of a particular control structure. The general control structures shown here can be extended to other prefractionator arrangements as well like Kaibel column.