Production scheduling of a large-scale industrial continuous plant: Short-term and medium-term scheduling

In this work, we describe a framework for short-term and medium-term scheduling of a large-scale industrial continuous plant. For medium-term scheduling, two sub-problems are solved using a rolling-horizon based decomposition scheme. An upper-level model is used to find the optimal number of products, and the length of the time horizon to be considered for solving the lower level short-term scheduling problem. At the lower level, we proposed an improved model for short-term scheduling of continuous processes using unit-specific event-based continuous-time representation. The proposed formulation is demonstrated on a large-scale industrial case study comprising up to 100 units with 1/3 processing and 2/3 storage units operating in a continuous-mode for producing more than 100 different products over a one month time horizon.