Intermediate reboiler and condenser arrangement for binary distillation columns

The most thermodynamically efficient configuration for adding or removing heat from an intermediate location of an ideal binary distillation column distilling pure products is derived The optimal policy requires that preconditioning of the feed be part of the overall decision-making process. The optimal configuration can be determined through the use of two parameters, alpha(IR) and alpha(IC), that are solely functions of feed composition. Simple and readily usable heuristics using these parameters are developed that help instantly identify the most efficient selection among (I) totally vaporizing and returning a side-draw liquid stream from an intermediate location of the distillation column, (2) partially ol totally vaporizing a portion of the given saturated liquid feed, (3) partially or totally condensing a portion of the given saturated vapor feed, and (4) totally condensing and returning a side-draw vapor stream from an intermediate location of the distillation column.