Online switching of entrainers for acetic acid dehydration by heterogeneous azeotropic distillation

► A more energy-efficient HAD with PX as the entrainer is designed in the study. ► An entrainer can be changed from IBA to PX without the need of shutdown and startup. ► Side-draw flow control can create PX imbalance if there is flow measurement bias. ► Temperature control strategy is proposed to maintain PX inventory in the HAD column.