Simulation Of ACN Butadiene Extractive Distillation Process By Extractive Dividing Wall Column

Chemical engineering industry has been a constantly increased the effort to design and build more energy saving processes. Distillation is one of the most significant processes for separating mixtures. Divided-wall column (DWC) could separate a feed mixture into three products in a single column. The energy consumption, cost of equipment, plot area used in the conventional distillation column sequence could be greatly reduced by DWCs. The conventional extractive distillation sequence could separate C4 mixtures, which include butane, isobutene, etc. Solvents used in the extractive distillation column are acetonitrile (ACN) and water.In this thesis, the design and optimization of the DWC distillation processes for conventional extractive distillation simulation production were studied. First, the conventional distillation process for ACN butadiene production was simulated based on a real industrial process, and the simulation results were very close to the industrial data. Then the two extractive distillation columns and the solvent recovery columns in the conventional distillation process were integrated by an extractive DWC (EDWC). For the extractive separations of the C4 mixtures, although the EDWC can be more thermodynamic efficient than the conventional extractive distillation column flowsheet, the chosen entrainers can frequently enable the former to be less economically favorable than the latter.Both conventional and non-conventional distillation arrangement have been compared. In order to minimize the equipment expenses and operation cost, the simulation has optimized the traditional process through thermally coupled distillation technology. By simulating and optimizing the equipment and operation parameters, we obtained the most effective results, making this simulation reliable and purity of the butadiene product has reached an industrial level of 99.2% purity. The optimum EDWC design has a total annual cost (TAC) of 1.45* 106 USD/year, which is better than that of the conventional distillation processes TAC of 1.62* 106 USD/year. This represents a decrement of 10% in the total annual cost. The simulation results prove the advantages of using EDWC for the butadiene extraction process.