Prefractionation to reduce energy consumption in distillation without changing utility temperatures

✍ Scribed by Rakesh Agrawal; Zbigniew T. Fidkowski; Jianguo Xu

• Book ID: 102697461
• Publisher: American Institute of Chemical Engineers
• Year: 1996
• Tongue: English
• Weight: 872 KB
• Volume: 42
• Category: Article
• ISSN: 0001-1541
• DOI: 10.1002/aic.690420804

✦ Synopsis

Abstract

Distillation systems composed of a prefractionator and a main column are introduced. The columns operate at different pressures, but the temperatures of the utilities are the same as for a single column performing the same separation. The energy integration of the columns is realized by condensing a vapor overhead from the prefractionator in an intermediate reboiler located in the stripping section of the main column or by boiling a bottoms liquid from the prefractionator in an intermediate condenser placed in the rectifying section of the main column.

Analysis is performed to determine feasible regions of operational parameters and to minimize vapor flows. A detailed simulation example of the benzene–toluene separation shows that for certain feed compositions it is possible to reduce energy requirements of a conventional binary distillation column by almost one‐third using this new distillation system. This savings is achieved without any change in the temperature of the utilities used.