Reactive scheduling using parametric programming

To address the various disruptive events that occur during process operations, reactive scheduling is commonly used. However, a major limitation of the existing reactive scheduling techniques is the response time, which might cause significant delay while the generation of a new schedule takes place. In this article, a novel approach is proposed to improve the efficiency of reactive scheduling and to avoid the resolution of a complex optimization problem when uncertain event occurs during the scheduling period. In the proposed method, reactive schedule is obtained from the solution of multiparametric programming problem, which is solved ahead of time and covers all possible outcomes of future uncertainty. The multiparametric programming problem is derived from a new reactive scheduling formulation, which integrates disruptive events (rush order and machine breakdown) as uncertain parameters in the process modeling. Several examples are presented to illustrate the effectiveness of the proposed approach. (C) 2008 American Institute of Chemical Engineers.