Optimization of cyclohexanone distillation process

Steady-state simulation of traditional cyclohexanone distillation process was established by Aspen Plus, and calculation for main equipments were carried out in this simulation. Analysis of gas-liquid phase composition in the light column was conducted, and the results showed that cyclohexanone composition on the fifth theoretical plate at the top of light column had reached the product quality requirements. Based on the process simulation, a new process of cyclohexanone distillation with side stream was proposed. Through modifying the cyclohexanone column, the light components were separated on the top of cyclohexanone column, and the cyclohexanone product was withdrawal by a side stream simultaneously. In the new process, the separation of light components and cyclohexanone purification were conducted in a single column, while the light column and auxiliary equipments in the conventional process were eliminated. The optimized simulation results showed that, the theoretical plate number of the new cyclohexanone column was 80, and the cyclohexanone product (mass fraction 99.8%) was extracted from the 10th theoretical plate at the top of the column. In the new process, the gas-liquid load in the cyclohexanone column was the same as that of the traditional scheme. As a result, the cyclohexanone column had the same diameter as the existing one, and 15 more theoretical plates were required on the top of the new column. Compared with the conventional process, the new process can save energy more than 25% and improve the yield of cyclohexanone product. Additionally, the new process had the advantages of saving construction land and equipment investment. © 2017, Chemical Industry Press Co., Ltd.. All rights reserved.