The extractive dividing-wall column (E-DWC) as process intensification can achieve more sustainable chemical process with economic and safe performance. However, the operation and controllability are in question and are biggest obstacle to the industrialization of extractive dividing-wall column. The coupling effect of E-DWC improves the thermal efficiency significantly but loses one control freedom and enhance interaction behavior compared with the conventional process. In this paper, we investigate the interaction behavior in E-DWC and illuminate the necessary of the extra control freedom to address the interaction behavior although the number of control freedom degrees are just enough for holding purity specification of three products.

To solve the coupling effect and interaction behavior, in this paper, the intermediate heating is used to add one control freedom to change the vapor split through directly increasing the flowrate of vapor. We use two systems-acetone and methanol, and bioethanol dehydration as cases to explore the controllability and operation of E-DWC. The results of dynamic simulation prove that the interaction behavior and coupling effect indeed cause poor controllability of E-DWC. Moreover, the intermediate heating strategy indeed is valid and can improve controllability of E-DWC significantly. The integral of squared error and deviation of product purity are reduced significantly both for two cases. Especially for acetone and methanol, the setting time and integral of squared error in the presence of +20% composition disturbance is reduced significantly.

作为过程强化的萃取式分隔壁塔（E-DWC）可以实现具有经济和安全性能的更可持续的化学过程。然而，操作性和可控性是有疑问的，并且是萃取式分隔壁塔工业化的最大障碍。与传统工艺相比，E-DWC的耦合效果显着提高了热效率，但失去了一种控制自由度并增强了交互行为。在本文中，我们研究了E-DWC中的相互作用行为，并阐明了额外的控制自由度以解决相互作用行为的必要性，尽管控制自由度的数量足以满足三种产品的纯度要求。

为了解决耦合作用和相互作用行为，本文采用中间加热来增加一个控制自由度，以通过直接增加蒸气的流量来改变蒸气的分配。我们使用丙酮和甲醇以及生物乙醇脱水这两种系统来研究E-DWC的可控性和操作。动态仿真结果表明，相互作用行为和耦合效应确实导致E-DWC的可控性差。而且，中间加热策略确实是有效的，并且可以显着提高E-DWC的可控性。在两种情况下，平方误差的积分和产品纯度的偏差均显着降低。特别是对于丙酮和甲醇，在+ 20％组分干扰的情况下，凝结时间和平方误差积分显着减少。