带有中间储罐的间歇精馏工艺动态控制模拟优化

Simulation and optimization of dynamic control on the middle vessel batch distillation process

甲酸甲酯-甲醇-水是化工生产过程中最常见的三元混合物之一。目前,间歇精馏工艺分离该三元混合物的研究较少,在动态控制方面也少有报道。本文研究了分离甲酸甲酯-甲醇-水的带有中间储罐的间歇精馏工艺动态控制模拟优化。利用Aspen Plus和Aspen Plus Dynamics软件,在稳态模拟的基础上,分别考察了液位控制结构和组分控制结构两种控制方案。结果表明,液位控制结构控制性能较差,达到稳定后甲醇和水的纯度较低。组分控制结构虽能提高产品纯度,但出现了较为严重的振荡现象。根据对组分控制结构的动态响应分析,本文提出了一种改进的组分控制结构,该控制结构能实现带有中间储罐的间歇精馏工艺的稳健控制,使各产品纯度得到提高。

The methyl formate/methanol/water is one of the most common ternary systems in chemical processes. There are few studies on the separation of the methyl formate/methanol/water using batch distillation process and the dynamic control strategies are rarely reported. In this paper, the batch distillation process of this ternary system with a middle vessel was studied and the dynamic control strategies for this process were optimized. Dynamic control strategies were studied by adding the level control structure and the composition control structure based on the steady-state results using Aspen Plus and Aspen Dynamics. The results showed that the level control structure performed poorly with low methanol and water purities after the steady state was reached. Though the composition control structure improved the product purities, the abnormal oscillations occurred. A modified composition control structure was developed after analyzing the results from the composition control structure. The results indicated that the new control structure yielded a robust control of the middle vessel batch distillation process and improved all the product purities.