Abstract To develop energy-saving, low consumption, green and clean production process of purified terephthalic acid (PTA), a coupling process of oxidation-multistage distillation was proposed based on the traditional PTA production process and distillation dehydration oxidation-distillation process using reaction heat. Three different integrated PX oxidation and distillation dehydration process schemes were established and simulated by using ASPEN PLUS software. Simulation results showed that the oxidation-dehydration coupling process directly using the reaction heat as the rectification heat source, and the refined mother liquor as the dehydration tower reflux could greatly reduce the consumption of dehydration energy, deionized water and raw material. Compared with the traditional process, the dehydration energy consumption was reduced by 76%, deionized water was decreased by 65% and PX usage was reduced by 1.65 kg/t-PTA. On this basis, an optimized multi-stage distillation process was proposed to utilize acetic acid solvents of different concentrations from the dehydration process. Calculation results showed that the new process could further reduce the consumption of acetic acid by 0.32 kg/t-PTA and wastewater by 64%. The oxidation-multistage distillation coupling process may be promising for PTA production with energy-saving, and emission reduction.
