Study of the divided wall column controllability: influence of design and operation

The main objective of this work is to study the influence of design and ope rating conditions on the divided wall column (DWC) controllability. Firstly , two designs for which the total distillation cost is minimised are compar ed. For each design, different optimal reflux to minimum reflux ratio is as sumed. Secondly, three non-optimal designs are compared with an optimal one . Adding trays to different column sections, the distribution of the distil lation effort is changed. The effect of this change on the controllability is studied. The DWC has extra operation degrees of freedom and the operatio n that minimises the boilup is searched. The influence of the operating con ditions over the controllability is studied comparing optimal and non-optim al nominal operations. (C) 2000 Elsevier Science Ltd. All rights reserved.