Abstract: With the continuous development of ethylene industry, the separation and utilization of by-product cracking C₅ component to improve the added value of C₅ has become the trend of development in the future. Taking n-pentane/1-pentene system as an example, the extractive distillation process of n-pentane/1-pentene system was simulated using three common extractants, such as acetonitrile, N-methylpyrrolidone and 2-butanone, the simulated energy consumption of different extractants was compared under the conditions of specified purity (≥ 95%) and recovery (≥ 90%), the corresponding mathematical model was established, and the extraction process was analyzed and optimized. The effects of other factors such as the number of trays, reflux ratio, feed position and extractant dosage were further optimized. The results showed that N-methylpyrrolidone was more reasonable as extractant. The optimized operation conditions were as follows: the number of theoretical trays was 65, the feeding positions of raw materials and extractants were at the 45^th and 5^th trays respectively, the reflux ratio was 3.7, and the extractant flow rate was 1 030 kg/h. Under these conditions, the purity of n-pentane was over 95%, and the recovery was over 91%.

Key words: n-pentane, 1-pentene, extractive distillation, acetonitrile, N-methylpyrrolidone, 2-butanone