SCI和EI收录∣中国化工学会会刊

Chin.J.Chem.Eng. ›› 2018, Vol. 26 ›› Issue (10): 2040-2047.DOI: 10.1016/j.cjche.2018.05.003

• Separation Science and Engineering • Previous Articles     Next Articles

Conceptual design of an extractive distillation process for the separation of azeotropic mixture of n-butanol-isobutanol-water

Hengjun Gai, Kaiqiang Lin, Yirong Feng, Meng Xiao, Kai Guo, Hongbing Song   

  1. College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
  • Received:2017-11-20 Revised:2018-05-02 Online:2018-11-14 Published:2018-10-28
  • Contact: Hongbing Song,E-mail address:cehbsong@qust.edu.cn
  • Supported by:

    Supported by the National Key Technology Support Program of China (2014BAC10B01), the National Natural Science Foundation of China (21406123), and the Key Scientific and Technological Project of Shanxi Province (MH2014-10).

Conceptual design of an extractive distillation process for the separation of azeotropic mixture of n-butanol-isobutanol-water

Hengjun Gai, Kaiqiang Lin, Yirong Feng, Meng Xiao, Kai Guo, Hongbing Song   

  1. College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
  • 通讯作者: Hongbing Song,E-mail address:cehbsong@qust.edu.cn
  • 基金资助:

    Supported by the National Key Technology Support Program of China (2014BAC10B01), the National Natural Science Foundation of China (21406123), and the Key Scientific and Technological Project of Shanxi Province (MH2014-10).

Abstract: In many chemical processes, large amounts of wastewater containing butanol and isobutanol are produced. Given that n-butanol-isobutanol-water can form triple azeotrope, high-purity butanol cannot be recovered from the wastewater by ordinary distillation. To economically and effectively recover butanol from this kind of wastewater, 1,4-butanediol is selected as an extractant to break the formation of the azeotropes, and a doubleeffect extractive distillation process is proposed. The conceptual design of the proposed process is accomplished based on process simulation. With the proposed process, the purity of recovered butanol and water is greater than 99.99 wt%. In comparison with the conventional azeotropic distillation process, economic analysis shows that the operating cost of the proposed process is lower:when the capacity of wastewater treatment is 100 t·h-1, the total operating cost decreases by 5.385×106 USD per year, and the total annual cost of the new process decreases by 5.249×106 USD per year. In addition, in the extractive distillation system, variable effects on separation purities and cost are more complex than those in the ordinary distillation system. The method and steps to optimize the key variables of the extractive distillation system are also discussed in this paper and can provide reference for similar studies.

Key words: Extractive distillation, Triple azeotropic system, Conceptual design, Butanol dehydration

摘要: In many chemical processes, large amounts of wastewater containing butanol and isobutanol are produced. Given that n-butanol-isobutanol-water can form triple azeotrope, high-purity butanol cannot be recovered from the wastewater by ordinary distillation. To economically and effectively recover butanol from this kind of wastewater, 1,4-butanediol is selected as an extractant to break the formation of the azeotropes, and a doubleeffect extractive distillation process is proposed. The conceptual design of the proposed process is accomplished based on process simulation. With the proposed process, the purity of recovered butanol and water is greater than 99.99 wt%. In comparison with the conventional azeotropic distillation process, economic analysis shows that the operating cost of the proposed process is lower:when the capacity of wastewater treatment is 100 t·h-1, the total operating cost decreases by 5.385×106 USD per year, and the total annual cost of the new process decreases by 5.249×106 USD per year. In addition, in the extractive distillation system, variable effects on separation purities and cost are more complex than those in the ordinary distillation system. The method and steps to optimize the key variables of the extractive distillation system are also discussed in this paper and can provide reference for similar studies.

关键词: Extractive distillation, Triple azeotropic system, Conceptual design, Butanol dehydration