The naphtha splitter process is a representative distillation processused in the refinery industry. To improve the fractionation of the naphtha boiling range derived from hydro-treatment, naphtha feedstock is sequentially separated into light naphtha, heavy naphtha, and light kerosene. Conventional naphtha splitting columns can be retrofitted to an advanced configuration requiring less energy consumption with consequently less CO₂ emission. A systematic design for retrofitting naphtha splitting columns for the thermally coupled distillation sequence (TCDS) that addresses the bottleneck phenomenon by integration of existing shells was developed in this study. The results showed that the operating cost could be reduced drastically by novel combination of the TCDS and a side reboiler with minimal process modification.