The objective of this study was to find process simulations of the plant-wide scale lactic acid recovery process using thermally coupled distillation columns to mitigate the remixing effect. The remixing effect has been widely discussed because in a conventional column arrangement it induces a need for a significant amount of energy for repurification in lactic acid recovery processes. One way to overcome high energy consumption is by using thermally coupled distillation columns. This paper suggests and compares two types of thermally coupled distillation columns applied to the plant-wide scale lactic acid recovery process for removing the remixing effect considering a heavy organic impurity and lactic acid oligomerization in the process. The equilibrium stage model based on the RADFRAC module of Aspen Plus was employed for simulating the thermally coupled distillation columns. Simulation results showed that thermally coupled distillation columns can eliminate the remixing effect and reduce energy consumption compared to conventional lactic acid recovery processes.