Thermally coupled distillation arrangements are
increasingly interested in chemical process industries
because of their potential in energy savings [1]. For
separation of three-component mixture, the Petlyuk
configuration [2] or fully thermally coupled distillation
arrangement shown in Fig. 1 (a), has been reported to
require 30%-50% less energy comparing to traditional
two-column sequences [3]. Often the Petlyuk configuration
is associated to the divided wall column (DWC)
for fully thermally coupled distillation as shown in
Fig. 1 (b), which can be considered as thermodynamically
equivalent with the former assuming that no heat
transfer across the wall occurs [4].