Abstract: The design of the first para-xylene complex using LD PAREX technology in the world was introduced in terms of material balance, unit capacity, operating conditions, process flow, and energy consumption and was compared with the traditional process. In the design, the heat integration center was raffinate column instead of xylene column and the desorbent rerun column was deleted; the flow scheme of hot high pressure separator plus cold low pressure separator was used for isomerization sector, the isomerization distillation and xylene separation sector was integrated optimally and the deheptanizer was canceled. The energy consumption per ton para-xylene was reduced from 7 964 MJ/t to 6 706 MJ/t, about 15.8%, due to relaxation of feed contaminant limit for adsorption separation unit and reduction of desorbent circulation quantity, which proves the LD PAREX technology advancement.

Key words: para-xylene, adsorption separation, light desorbent , p-diethyl benzene, toluene