Modifier Adaptation using transient measurements to compute plant gradients *

Abstract

Traditionally, Modifier-Adaptation (MA) proceeds by iteratively adjusting the optimization problem with modifiers calculated from steady-state information obtained after each real-time optimization (RTO) execution. This implies a long convergence time. This paper presents one approach to speed up the convergence to the optimum by using transient information of the process. This technique is based on a recursive identification algorithm to estimate process gradients from transient measurements, achieving the plant optimum faster than traditional MA techniques. The method has been implemented in the operation of a depropanizer distillation column in order to show its advantages.