Periodic Scheduling of an Industrial Batch System using a RTN Continuous-time Formulation

摘要

This paper addresses the optimal periodic scheduling of a resource constrained, four batch digester plant. Focus is set on the different alternatives that exist to model the sharing of the limiting resource (steam) among the digesters and their influence on the computational performance of the developed continuous-time, Resource Task Network based mathematical formulation. Three possibilities were considered, with the one that considers exclusively fixed duration tasks and treats steam as a discrete resource showing the best computational performance. This decreases significantly, first when the steam resource is made continuous and then when considering variable duration tasks. These results suggest that is preferable to represent a process by using simple tasks instead of complex ones, even if a larger number of tasks is required.