Abstract: Using N,N-dimethylformamide (DMF) as the extractant, orthogonal experiments were employed to optimize the operating parameters for the separation of isoprene and n-pentane by dividing-wall extractive distillation. The results showed that the optimal operating conditions at the feeding rate of 1000 kg/h were as follows: reflux ratio of 6, DMF and feed introduced at the 11th and 28th trays, respectively, mass ratio of DMF to isoprene-n-pentane of 2, side draw position at the 54th tray, and side draw flow rate of 756 kg/h. Under these optimal conditions, the mass fractions of n-pentane, isoprene, and DMF in the product were 99.89%, 99.96%, and 99.99%, respectively, meeting the purity requirement of greater than 99.0%. Aspen Plus was used to simulate the conventional distillation and dividing-wall extractive distillation processes for separating isoprene and n-pentane. The simulation results showed that, under the same feed conditions and product purity requirements, the use of the dividing-wall extractive distillation process reduced the condenser and reboiler duties by 36% and 27%, respectively, compared to the conventional extractive distillation process.

Key words: dividing wall extractive distillation, isoprene, n-pentane, N,N-dimethylformamide, orthogonal experiment