Graphical correlation of the number of stages with the reflux for ideal and azeotropic systems
Advancing the chemical engineering fundamentals
Distillation, Absorption & Extraction - II (T2-10b)
Keywords: Gilliland, number of stages correlation, rectification, reactive distillation
Gilliland made a data compilation of ideal distillation systems from the literature and found a graphical correlation of the number of stages with the reflux. Several authors have found equations to fit these graphical correlations, but the feed plate was not assured at its optimum and there was not a distinction between the number of stages of the stripping and enrichment sections. Our goal is to recalculate the Gilliland’s proposed processes optimizing the feed plate by rigorous simulation and checking the influence of both sections separately. The azeotropic systems do not follow the graphical tendency of the ideal ones and they were not graphically correlated by Gilliland. In this work, we take also into account the influence of the reflux on the number of stages for non ideal systems. A correlation equation for both sections is proposed.
The graphics obtained show, for each column section, one horizontal and one vertical asymptote according the minimal number of stages and minimal reflux. Each distillation section has its own minimal reflux and the overall minimal reflux for the column correspond to the section of higher minimal reflux. The minimal number of stages for the entire column is also obtained as a sum of the minimum number of stages for each section. Finally, its capability on correlating a reactive distillation column is also evaluated.
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Presented Monday 17, 15:40 to 16:00, in session Distillation, Absorption & Extraction - III (T2-10b).
