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An HIDiC(Heat-integrated distillation column) can provide great energy savings comparing with conventional distillation columns,with the heat integration at multiple locations between the rectifying and stripping sections.The ideal HIDiC (with heat integration between the whole rectifying section and the whole stripping section) are less efficient when the column has flat temperature profiles and high products purity.The HIDiC system with a small number of intermediate external heat exchangers can improve this kind of separation or shows comparable energy savings to ideal HIDiC.The locations and sizes of the external heat exchangers are key decision variables and should be considered deliberately to maximize energy efficiency and separation ability in process development.We compare the energy efficiency of the different heat integration alternatives between the rectifying and stripping sections for three binary systems.Three example systems i.e.,propylene/propane,benzene/toluene,and ethylene/ethane binary mixture,are employed to evaluate the proposed configurations.We develop a systematic method to determine heat integration locations in order to find the point of minimum energy consumption.We show how the McCabe Thiele diagram in the HIDiC scheme can be used to determine the most favorable match of location to transfer heat from the rectifying section to the stripping section.The McCabe-Thiele diagram in its most simple form provides a graphical solution to the classical separation problem as well as HIDiC.The distance between the equilibrium and the operating lines can be considered as the driving force for separation.The distribution of driving forces inside a column can be illustrated using the McCabe-Thiele diagram for binary separation.This strategy of matching using the McCabe-Thiele diagram is generally applicable to any separation,and it also helps to identify energy efficient heat integration approaches.A novel synthesis of a heat integrated distillation column using external heat exchanger for an effective arrangement of heat integration between the rectifying and stripping sections is proposed employing the McCabe-Thiele diagram.