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Minimum energy demand of distillation columns with multiple feeds
Author(s) -
Glanz Stephan,
Stichlmair Johann
Publication year - 1997
Publication title -
chemical engineering and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.403
H-Index - 81
eISSN - 1521-4125
pISSN - 0930-7516
DOI - 10.1002/ceat.270200206
Subject(s) - fractional distillation , distillation , process engineering , chemistry , chromatography , sequence (biology) , energy (signal processing) , on demand , product (mathematics) , ideal (ethics) , mathematics , mathematical optimization , computer science , engineering , statistics , biochemistry , multimedia , geometry , philosophy , epistemology
Distillation columns with multiple feeds are often used in processes for the separation of multicomponent mixtures. The minimum energy demand of such columns is determined via the minimum reflux and reboil, respectively. A novel method for directly calculating the minimum reflux ratio is presented in this paper. Applicable to ideal, nonideal and azeotropic mixtures the method is based merely on the knowledge of vapor‐liquid equilibrium of the feed mixtures. This knowledge allows the determination of the internal concentration profile near the feed entry and, in turn, the calculation of both minimum reflux and optimal sequence of feeds. This sequence of feeds depends on feed compositions and product compositions, as well. Surprisingly, sometimes a multiple feed entry requires a higher energy demand than premixing the feed streams.