Simulation And Optimization Of An Ethyl Acetate Batch Reactive Distillation

As a very important organic material, ethyl acetate is used extensively. Nowadays in our country, the common method of producing ethyl acetate is the esterification in which 98% concentrated sulfuric acid is used as catalyst. The esterification reaction between ethanol and ethanoic acid to ethyl acetate is reversible. Ethyl acetate, ethanol and water can form binary or ternary azeotropes. Therefore, it is very difficult to obtain ethyl acetate of high purity. In this article a batch reactive distillation for the preparation of the ethyl acetate of high purity and its process simulation have been studied by using Aspen Plus, a simulation software of chemical technology. The result of simulation is helpful to the practical operation.The diameter of packed distillation column used in this experiment is 25mm. The height of column is 1400mm, and the height of packing is 1300mm. The packing in the column is aφp3.0*3.0θnet of ring-shaped which is made of stainless steel. The quantity of ethanoic acid and ethanol is 60g and 48g respectively. The reflux ratio is 3, and the column reactor heating temperature is 60℃. When the temperature of column reactor reaches 74℃, the reaction is over. Using a gas chromatograph, we analyzed the constituent of the product in the column top, the result showed that the mass fractions of ethanol, ethanoic acid, ethyl acetate and water are 11.31%,0%,79.45% and 9.24%, respectively.Based on the experimental data, an ethyl acetate batch reactive distillation was simulated and optimized by using Aspen Plus. Choosing BatchSep model in Aspen Batch Distillation, and using NRTL activity coefficient model as well as Hayden-O'Connell equation of state, we calculated the constituent of the product in the column top and obtained that the mass fractions of ethanol, ethanoic acid, ethyl acetate and water are 10.2%,0%,80.78%and 9.02%, respectively. This simulation result is very close to the experiment. Especially, the error of the mass fraction of the ethyl acetate, is within 3%. It proves the reliability of the simulation.In order to increase the mass fraction of ethyl acetate in the product, an optimization to the simulation has been carried on. After the optimization of the reflux ratio, the column reactor heating temperature and the feed mole ratio of ethanol to ethanoic acid, we can receive the optimum process conditions that are the reflux ratio is 5.1, the column reactor heating temperature is 120℃, and the feed mole ratio of ethanol to ethanoic acid is 1.04:1. Using the optimized process conditions to simulate, we can get that the mass fraction of the ethyl acetate is 82.13%. Under these optimized conditions, The experiment was improved and the result showed that the mass fraction of ethyl acetate in distillate is 81.95%. It is in agreement with the result of simulation and is improved compared with previous optimization. So, it proves the reliability of the optimization and the correctness of the result.