Chinese Journal of Chemical Engineering ›› 2019, Vol. 27 ›› Issue (4): 869-876.doi: 10.1016/j.cjche.2018.10.003

• Separation Science and Engineering • Previous Articles     Next Articles

A novel kind of multiple steady states characteristics in the dividing wall column

Erwei Song, Zengxi Li, Erqiang Wang   

  1. School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2018-05-23 Revised:2018-07-18 Online:2019-04-28 Published:2019-06-14
  • Contact: Zengxi Li, Erqiang Wang;
  • Supported by:
    Supported by the National Natural Science Foundation of China (21376240).

Abstract: In this article, one kind of multiple steady states (MSS) phenomenon was investigated for a dividing wall column (DWC). The four-section model constructed in Aspen Plus was employed to simulate two DWC cases:mixture of n-hexane, n-heptane and n-octane; system of methanol, ethanol and n-propanol. It can be seen that there is a range of vapor split ratio in which multiple solutions of reflux ratio exist for fixed DWC configuration with the same feed and product streams. The width and the curve shapes of the MSS region, and the number of solutions change with the liquid split ratio. This MSS phenomenon was further explained using the component recovery around the prefractionator and the component recycling flow inside the DWC. This MSS phenomenon is helpful for DWC design by knowing the probable existence of multiple solutions in advance.

Key words: Dividing wall column, Multiple steady states, Vapor split ratio, Liquid split ratio, Recycling flow