Abstract: The model of simulated moving bed (SMB) for para-xylene separation by adsorption was established. The influence of the bed number ratio in each functional zone, the void volume between beds, and the total bed number on adsorption performance was investigated. Results showed that the optimized ratio of the bed number in adsorption zone over that in the purification zone is in the range of 0.5-0.7; the optimized ratio of the bed number in desorption zone / the purification zone is in the range of 0.4-0.5. The suitable ratio for buffer zone over total bed number is 8.5%-13.0%. Increasing the total bed number and decreasing the void volume can improve the separation efficiency of the process. Test results indicated that the optimized bed numbers in each zone (desorption, puri?cation, adsorption, and buffer zone) is 3, 7, 4, 2. This configuration reduces the number of adsorbent bed and adsorption tower under the premise of basically the same process performance.

Key words: para-xylene, adsorption separation, simulated moving bed, process simulation