| Abstract
| - A previous paper introduced the concept of traveling distance to quantify how much the composition profilein a distillation column has to change when certain tray temperatures are held constant under single-endtemperature control. The larger the traveling distance for a given temperature-control selection, the slowerthe composition dynamics and, hence, the poorer the control performance are expected to be. This workgeneralizes the concept of traveling distance in distillation-temperature control for different levels of complexityin a ternary distillation column separating components A, B, and C, in order of decreasing volatility. For thedirect separation between A and B/C with a high purity of A at the top, the analysis shows that the conflictbetween process and control direction becomes more severe (larger traveling distance) with (1) increasingoverhead purity of A, (2) decreasing relative volatility between light and heavy key components (A and B,respectively), (3) increasing relative volatility between the heavy and heavier-than-heavy key components (Band C, respectively), and (4) decreasing feed composition of the light key component (A). The results can beinverted to the indirect separation between A/B and C with a high purity of C at the bottom, while substitutingheavy for light in the above conclusions.
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