乙酸丁酯反应精馏过程模拟设计

反应精馏偶合了反应和精馏两种单元操作,通过精馏促进反应,可以提高反应转化率和收率,为可逆反应的化工过程生产提供了新的设计途径。基于严格热力学分析计算,利用计算机模拟和优化手段。提出了乙酸丁酯反应精馏、分离纯化的生产流程。采用UNIQUAC方程表征乙酸-正丁醇-乙酸丁酯-水四元非理想体系的汽液平衡,首先,根据实验数据回归了热力学模型中的交互作用参数,并预测了体系中5个共沸物组成,模型的计算结果与实际数据吻合。基于平衡级模型,提出了由平衡反应器、反应精馏塔、倾析器和纯化塔构成的可行流程,对提出的设计流程进行了模拟、优化,得到了操作工艺参数。模拟结果对工业过程的设计和改造具有一定的指导意义。

n-butyl acetate synthesis via reactive distillation: thermodynamic, process design

Design of a complete reactive distillation column system for the production of n-butyl acetate by the esterification of n-butanol with acetic acid has been developed. Thermodynamic aspects of the considered system are discussed. Firstly, UNIQUAC model is used to calculate the activity coefficients of the high non-ideal liquid phase. Then thermodynamic model parameters set has been established with excellent prediction of the compositions and temperatures for the complex mixture, which contains only four components, but forms five azeotropes. The developed model is verified by experiment result. Then the whole reactive distillation process is developed. The overall design of this n-butyl acetate (BtAc) produce system includes one equilibrium reactor, one reactive distillation column, one decanter, and one purified distillation column. n-butanol conversion more than 98% accompanied with n-butyl acetate purities of 96% were achieved. Optimum operating conditions of the overall system are studied to minimize total energy consumption of the overall system while meet product specification. The results will provide fundamental guide for the industrialization design.