Abstract: A steady-state model was established by Aspen Plus software for the isomerization reaction process of C₈ aromatics in the second p-xylene (PX) unit of SINOPEC Hainan Petrochemical Corporation, andthe Rplug module was selected as the reactor model.The results of model validation showed that the simulated valueswere in good agreement with the actualindustrial calibration values, indicating that the prediction results of the model were reasonable and reliable. This model was used to further analyze the influence of key process operating parameters such as reaction temperature, pressure, and feed hydrogen-to-hydrocarbon ratio on the performance of isomerization reaction. The results showed that under the promise of meeting the requirements of isomerization activity, the adjustment of pressure and temperature should conduct simultaneously. The temperature and pressure had little effect on the yield of PX.Lower temperature, higher pressure and suitable ratio of hydrogen to hydrocarbon were favorablefor ethylbenzene (EB) conversion,while lower temperature, lower molar ratio of hydrogen and medium pressure were favorable for reducing C₈ aromatics loss.Optimizing the ratio of hydrogen to hydrocarbon to 3.9 could maximize the conversion of EB and the generation of PX. The optimum reaction temperature was347℃, the pressurewas0.46 MPa, and hydrogen-to-hydrocarbon ratio was 3.9.The EB conversion, PX yield and PX mass flow rate could be effectively increased by adjusting the isomerization operation parameters according to the simulation results.

Key words: Aspen Plus software, C₈ aromatics isomerization, steady state simulation, p-xylene