Integrated scheduling of the drying process in a sawmill

Abstract

Wood drying is a critical stage in the sawmill production process since it will enable achieving the wood characteristics needed to meet market requirements. Generally, it is a batch process that is carried out in drying kilns that operate in parallel out of phase. Boilers fed with by-products generated in other productive sawmill stages are used to cover the energy needs of the process. For their efficient performance, dryers filling and scheduling must be simultaneously planned with boiler feed and operation. In this article, these decisions are addressed through a mixed integer linear programming model (MILP) using state-task network concepts based on discrete time formulation. The model is tested using various objective functions that represent different work criteria related to sawmills, achieving highly significant results for the performance of this industry.