(383a) Understanding and Comparing Energy-Intensification Strategies for Extractive Distillation Processes

Extractive distillation remains the most widely-used method for separating azeotropic mixtures. The most commonly encountered situation is the case of a minimum-boiling azeotrope separated by a heavy entrainer. Such processes generally consume a significant amount of energy, and there is considerable interest in reducing this consumption. Various methods for reducing energy consumption include heat integration [1], heat pumps [2], thermal coupling [3, 4] and side-streams [5, 6]. Although a number of different methods have been proposed for intensification of extractive distillation processes, there is little general guidance about which method is likely to work best for a given situation.

Therefore, in this work, a new dimensionless ratio R_CB is proposed as a metric to assess energy-saving strategies for extractive distillation processes [7]. R_CB is the ratio of the flow rates of the entrainer (C) and the heavy product (B). The metric is used to compare six alternative intensified sequences. Seventeen chemical systems comprising a binary minimum boiling azeotrope and a heavy entrainer are optimized for each of the intensified sequences. Heuristics for the selection of energy intensification strategies based on the value of R_CB are proposed.

References

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7. Chien, C. K.; Ward, J. D. A new metric for the evaluation and selection of energy-intensified extractive distillation sequences. Sep Purif Technol 2023, 320. DOI: 10.1016/j.seppur.2023.124165.