Use of Continuous Distillation Columns for Batch Separation

• Published in: Chemical engineering research & design 1997, Vol.75 (6), p.609-619
• Main Author: Mujtaba, I.M.
• Format: Article
• Language: English
• Subjects: batch distillation; continuous column; multi-pass operation; multiple duties; reflux ratio
• ISSN: 0263-8762
• DOI: 10.1205/026387697524137

Over the last few decades many alternative column configurations and modes of operation have been suggested for batch distillation. This paper addresses the potential use of continuous distillation columns for the batch separation task. It is shown that under certain circumstances the conventional dynamic batch operation (inherent with a batch distillation column) can be replaced by the steady state operation of a continuous column without significant compromise of the recovery and energy consumption. This allows steady state modelling and optimization as opposed to dynamic modelling and optimization. Multi-Pass Sequential Steady State (MPSSS) operation is suggested to achieve high recovery of species in short operation time and low energy cost (meaning high productivity). Multi-pass operation achieves better recovery compared to conventional operation for the same energy consumption and operation time. The performance of a continuous column un dergoing multiple separation duties is also addressed in this work. It is shown that by choosing an optimal feed rate, an existing continuous column can be used effectively for separating multiple binary mixtures with different ‘degrees of difficulty’ of separation.