Improved operational policies for batch extractive distillation columns

Journal Article · Sat Feb 01 04:00:00 EST 1997 · Industrial and Engineering Chemistry Research

DOI:https://doi.org/10.1021/ie960343z· OSTI ID:452293

Safrit, B T; Westerberg, A W ^[1]

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1. Carnegie Mellon Univ., Pittsburgh, PA (United States)

The authors and others have previously developed insights into batch distillation when using a middle vessel batch column. They extended earlier work on reachable product regions for continuous columns to this and other batch column configurations. The work also examined the use of a continuously flowing extractive agent to facilitate the separation of azeotropic mixtures. A middle vessel batch column has both an enriching and stripping section and thus both a distillate and bottoms product. In many ways it is just like a traditional continuous column, but the authors feed it by charging a middle tray having a very large holdup (a pot or still) with the initial feed. The work compared running this column with running a batch rectifier for an azeotropic mixture when using an extractive agent. They showed that both are often able in theory to recover all of the distillate component in relatively pure form, with the middle vessel accomplishing this by steering the still pot composition against time through the choice of reflux, reboil, entrainer, and product rates. The middle vessel also requires a much smaller pot, as the authors can continually remove and recycle the extractive agent. In this work the authors show the sensitivity of the separation`s profit to the entrainer flow rate, the operation`s switching times between fractions, and the bottom flow rate policy for an extractive middle vessel batch column. They illustrate with an example problem.

• OSTI ID: 452293
• Journal Information: Industrial and Engineering Chemistry Research, Journal Name: Industrial and Engineering Chemistry Research Journal Issue: 2 Vol. 36; ISSN 0888-5885; ISSN IECRED
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
AZEOTROPE
DESIGN
EFFICIENCY
EXTRACTION COLUMNS
FLOW RATE
PROCESS CONTROL