Batch extractive distillation: The process and the operational policies

Z. Lelkes, P. Lang, P. Moszkowicz, B. Benadda, M. Otterbein

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The batch realisation of the extractive distillation and the role played by the different steps in the process are analysed and on the basis of this analysis several operational policies are presented. The different BED policies are studied by simulation and compared (with the example of the mixture acetone-methanol + water). A method is suggested for the comparison of the different BED operational policies. In a BED process the mole fraction of the more volatile component (A) in the distillate (x(d,A)) can be influenced not only by the variation of reflux ratio (R) but also by changing the flow rate of the solvent (F). The simulation results are experimentally investigated and verified for each operational policy. The original R = const. policy is modified by shortening the second preparatory step of the BED (R = ∞, F > 0). The possibilities of performing a constant distillate composition (X(d,A) = const.) policy are discussed. In order to increase the efficiency of the modified R = const. policy further, it is combined with the X(d,A) = const. policy, maintaining a high value of X(d,A) for a longer period during the production of A by gradually increasing R or F or R and F simultaneously. The feasibility of the cycling policy is also studied for the BED.

Original languageEnglish
Pages (from-to)1331-1348
Number of pages18
JournalChemical Engineering Science
Issue number7
Publication statusPublished - Mar 27 1998



  • Batch distillation
  • Extractive distillation
  • Operational policies
  • Pilot-plant experiment
  • Simulation

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering

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