Centralized and hierarchical scheduling frameworks for copper smelting process

Optimal scheduling of copper smelting process is an ongoing challenge due to conflicting objectives of the various process units and the inter-dependencies that exist among these units. To design a scheduling framework, two potential alternatives – centralized and hierarchical approaches – can address those inter-dependencies in this process. These approaches represent the two extremes and the choice depends on the accuracy, reliability, and complexity of the scheduling task. In this study, optimization-based centralized and hierarchical scheduling frameworks are developed to find an optimal schedule for the smelting process, considering the inter-dependencies among process units. We propose a practical and effective coordination scheme for the hierarchical framework that finds a near-optimal schedule with reasonable computational demands. Two case studies are presented to demonstrate that the proposed hierarchical framework is capable of finding a near plant-wide optimum for the copper smelting process and it can be used in similar plant-wide scheduling applications.