STEADY-STATE DECOUPLING OF DISTILLATION-COLUMNS

Steady-state sensitivity of one-way decoupling to errors in decoupler gain is defined using Bristol's relative gain array, and applications to distillation are given. Columns controlled via manipulation of reflux, and boilup, conventional control, are prone to sensitivity problems whereas material balance controlled columns are not. In some columns sensitivities can be so high that one-way decoupling appears to be impossible to achieve. Past studies on distillation decoupling are examined in the light of the sensitivity results presented. One-way decoupling of conventional high-purity columns is shown to be approximately equivalent to material balance control. © 1979, American Chemical Society. All rights reserved.