Abstract: Using Aspen Plus software, a process model of separating aromatics from non-aromatics by extractive distillation with N-formylmorpholine (NFM) is set up based on vapor-liquid equilibrium data of NFM and hydrocarbons system. Simulation results show that the calculations agree well with the actual operation data. The effect of solvent/oil ratio, inlet temperature of lean solvent and benzene content in lean solvent on the separation is investigated. Optimum operation parameters are obtained as follows: solvent/oil mass ratio of 4.66, lean solvent inlet temperature of 112 ℃ and mass fraction of benzene in lean solvent of about 1%. Calculations under optimization conditions show that the yield and purity of benzene enhance significantly, they increase 0.6 and 0.06 percentage points, respectively.

Key words: extractive distillation, N-formylmorpholine, aromatic hydrocarbon, optimization