(324c) New Class of Thermal Coupling Links in Multicomponent Distillation

Thermal coupling links between distillation columns have been known to provide significant savings in heat duty requirements. Thermal coupling links are two way liquid-vapor communications between distillation columns. Historically, thermal coupling links have been between reboilers and condensers associated with streams of similar compositions. The Petlyuk column is a classic example of such a thermal coupling link. In this work, we introduce a new class of thermal coupling links that involves the elimination of reboilers and condensers associated with streams of dissimilar compositions. The well-known Brugma configuration for separating a four-component feed mixture is one such configuration that demonstrates this class of thermal coupling links between distillation columns. However, our generalized class includes many possible novel thermal coupling links between distillation columns which result in several hitherto unknown configurations. This new class of thermal coupling links not only has the potential to save operating costs but also to provide capital cost benefits through the reduction of number of distillation columns and elimination of reboiler and condenser heat exchangers. Additionally, side-streams can be strategically withdrawn from the resulting thermally linked sections which have the potential to further provide significant energy savings. We present a systematic framework to identify all possibilities to thermally couple two distillation columns producing streams of dissimilar compositions. This framework can be used as an underlying principle to synthesize configurations resulting from such a class of thermal coupling links.