带组分循环反应精馏合成丙酸正丙酯过程优化设计与控制

A reactive distillation process with component recycling is proposed to address the challenging operational issues for unfavorable volatility sequence in the reaction system. Taking the esterification of excess npropanol with propionic acid to produce n-propyl propionate as an example, a reactive distillation process with npropanol circulation was constructed. The pinch point of the binary vapor-liquid equilibrium of n-propyl propiate and n-propanol was determined by thermodynamic analysis, and the integrated process of reactive distillation was systematically studied to determine the purity of recycled n-propanol (X_ProOH). Using sequential optimization method, the operating parameters and structural parameters of the reactive distillation column and recovery column were determined with the minimum annual total cost (TAC) as the optimization objective. The results show that when X_ProOH=0.80, a trade-off between the reaction process of the reactive distillation tower and the separation process of the recovery tower is achieved, and the process parameters with minimum TAC are obtained. In addition, a composition/temperature-proportional control scheme is proposed to study the dynamic response performance of the closed-loop system when the disturbance of ±10% propionic acid feed flow is introduced.