Optimal event point determination for short - term scheduling of multipurpose batch plants via unit - specific event - based continuous - time approaches / Jie Li in Industrial & engineering chemistry research, Vol. 49 N° 16 (Août 2010)  

Optimal event point determination for short - term scheduling of multipurpose batch plants via unit - specific event - based continuous - time approaches [texte imprimé] / Jie Li, Auteur ; Christodoulos A. Floudas, Auteur . - 2010 . - pp. 7446–7469.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 16 (Août 2010) . - pp. 7446–7469

Mots-clés :	Continuous time Batchwise Multipurpose installation Scheduling Short term
Résumé :	In the past two decades, three types of continuous-time models have been developed for the short-term scheduling of multipurpose batch plants: sequence-based, slot-based, and event-based models. Both slot- and event-based models require an iterative procedure proposed by Ierapetritou and Floudas ( Ind. Eng. Chem. Res. 1998, 37, 4341) to determine the number of event points or slots, which results in increased computational time and no optimal number of event points or slots in some cases. In this work, we first enhance the recently proposed three-index unit-specific event-based model developed by Shaik and Floudas ( Ind. Eng. Chem. Res. 2009, 48, 2947) and extend it to handle different wait policies. Then, we develop a general framework to obtain the optimal number of event points where an iterative procedure is employed to obtain the maximum number of event points and determine the critical intermediate states. The approach proposed by Janak and Floudas ( Comput. Chem. Eng. 2008, 32, 913) is used to obtain the minimum number of event points. Based on the maximum and minimum numbers of event points, we propose a branch-and-bound strategy to obtain the optimal number of event points. To accelerate convergence, techniques for task prefixing in the shortest path are proposed. Furthermore, we propose some criteria to determine which tasks to split over multiple event points and the maximum number of event points over which to continue them. Several examples with different intermediate storage requirements such as unlimited intermediate storage (UIS) and finite intermediate storage (FIS) are solved to illustrate the potential and computational efficiency of the proposed framework.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901842k