An approximate design procedure of extended fully thermally coupled distillation columns (FTCDCs) is refined for the design of real system having non-ideal equilibrium relation. For high thermodynamic efficiency and reduced computational load, a structural design utilizing the minimum tray structure is implemented, and the design procedure to find operational variables for a given specification of products is explained in detail. The thermodynamic efficiency of several structures of the extended FTCDC is examined from their distillation lines adopted from the residue curve of equilibrium distillation having ideal efficiency. With the structure of the highest efficiency among various ones, the proposed design is applied to three real systems of different chemical groups. The design outcome of the systems shows the effectiveness of the proposed design procedure.