Abstract: With the help of Aspen Plus 10 and system model recommendator, the fractionation of No. 4 diesel hydrogenation unit in SINOPEC Maoming Companywas simulated, analyzed and optimized by Chao-Seader and Galyson-Streed thermodynamic models. The results show that the simulation results are in good agreement with the actual operation data of the unit. Through the analysis and optimization of feeding stage and feeding temperature of the cold and hot low pressure separator oil in the fractionator, and the matching adjustment of the heat exchanger flow, as well as the transformation of the cold and hot low pressure separator oil into the fractionator separately, the final heat exchange temperature of cold low pressure separator oil is raised to 210 ℃, the consumption of stripping steam in the fractionation process is reduced by 1.7 t/h, and energy-saving effect is remarkable.

Key words: diesel hydrogenation, low pressure separator, process simulation, heat exchanger networks