反应精馏合成乙酸乙酯的实验研究与模拟

Experiment and simulation of reactive distillation process for synthesizing ethyl acetate

本文以Amberlyst-36Wet离子交换树脂为催化剂,采用间歇搅拌釜式反应器,在消除内外扩散影响的条件下,测得不同温度下反应速率常数。研究自制反应精馏塔中(直径25 mm,高2.2 m)乙酸乙酯的合成工艺,得到反应精馏的工艺参数。在实验基础上,建立改进工艺的Aspen Plus模拟流程图。实验结果与模拟计算值吻合良好,表明所建立的Aspen Plus模型能够很好地描述反应精馏合成乙酸乙酯过程。以乙醇转化率、产品乙酸乙酯的收率和塔顶油相乙酸乙酯的质量分率为考察目标,通过流程模拟和灵敏度分析,确定该工艺的最佳工艺参数:精馏段、反应段和提馏段的理论板数分别为9、7和7;醋酸和乙醇的最佳进料位置在第9块和第16块塔板上;回流比R为1.6。在此工艺条件下,产品乙酸乙酯的含量是95.2%(wt),乙醇转化率为96.1%。

Excluding the influence of external and internal diffusion, the rate constant of synthesis of ethyl acetate catalyzed by Amberlyst-36 Wet ion exchange resin in the batch reactor was determined under the different temperature, then the reactive distillation process for ethyl acetate synthesis was discussed and the process parameters were obtained. Based on the experimental results, the flow diagram of ethyl acetate synthesis was established by using Aspen Plus. Simulation results agreed well with experimental ones, which indicated that the Aspen Plus model could describe the reactive distillation process. Being conversion of ethanol, the yield of ethyl acetate, and the product purity as the indexes of investigation, the optimal process parameters were determined through simulation and sensitive analysis. Theoretical stages of rectifying section, reaction section, and stripping section are 9, 7, and 7, respectively ; feed stage of acetate acid and ethanol were 9 and 16, respectively; and reflux ration was 1.6. Under this process condition the mass fraction of ethyl acetate in product is 95.2% and the conversion of ethanol is 96. 1%.