Process Assessment of Heterogeneous Azeotropic Dividing-Wall Column for Ethanol Dehydration with Cyclohexane as an Entrainer: Design and Control

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• 作者：Ye Li ; Ming Xia ; Weisong Li ; Junwen Luo ; Lei Zhong ; Shanyuan Huang ; Jian Ma ; Chunjian Xu
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2016
• 出版时间：August 17, 2016
• 年：2016
• 卷：55
• 期：32
• 页码：8784-8801
• 全文大小：1666K
• 年卷期：0
• ISSN：1520-5045

文摘

The heterogeneous azeotropic dividing-wall column (ADWC) features significant reduction of capital investment and energy consumption. Conventional azeotropic distillation sequences can be thermally coupled into two types of configurations of ADWCs, namely, the original ADWC with simple azeotropic–recovery section and the other with recovery section also serving as preconcentrator. The ADWC with a combined recovery–preconcentrator section has been investigated in both steady-state design and dynamic controllability. However, the original ADWC has only been proven to be more energy efficient than the conventional azeotropic–recovery column sequence, not compared with the conventional azeotropic–stripper column sequence. Furthermore, the dynamic performance of this ADWC are still unclear. Note that all the benefits of the ADWC are reasonable only under good dynamic controllability. Thus, in this work, we develop a comparative study of optimal design and dynamic performance of the ADWC with two conventional sequences by demonstrating ethanol dehydration using cyclohexane as an entrainer. The results show that the ADWC has significant capital investment reduction and energy savings compared to two conventional sequences. Because two reboiler duties are preserved in the ADWC, it has dynamic controllability comparable with that of a conventional azeotropic–recovery column sequence and dynamic controllability superior to that of a conventional azeotropic–stripper column sequence.