Abstract: An acetic acid dehydration system via azeotropic distillation in the device for pure terephthalic acid (PTA) process is simulated by Aspen Plus. The influence of methyl acetate (MA) on the energy consumption of this process is studied systematically. The data show that MA will accumulate in the dehydrating tower, and the load of the tower will linearly increase with increasing MA content. By setting up partial condensation equipments between the dehydrating tower and the phase resolver to bring the vapor phase with more MA into the recovery tower, the circulation rate in MA system can be reduced significantly, and thus the energy consumption in the dehydration tower decreases. These results should have certain guidance for the design and production of PTA dehydration process.