A technique to evaluate distillation-column control-system energy balance disturbance sensitivity and rejection ability using a steady-state column simulator is discussed. The sensitivity analysis technique can be used in conjunction with existing control system design tools that evaluate control loop interaction, sensitivity, and stability such as singular value decomposition (SVD) and relative gain array (RGA). The disturbance rejection ability of dual-ended and single-ended control schemes using product composition, tray temperature, or internal tray composition measurements can be evaluated for column disturbances such as feed composition changes and operating pressure changes. The assumption is made that material balance disturbances can be handled by feedforward ratio control of the product and feed flow rates.
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