Towards improved scheduling: an analysis on time-steps, time-horizon, and rescheduling

Decision-making capabilities and solution approaches for industrial scheduling operations are often inefficient. Both the academic literature and industry require further investigation of scheduling strategies and methodologies to achieve further breakthroughs, in which a proper selection of modelling and optimisation parameters is imperative. This work investigates the impact of time-step size and time-horizon length on multiple scheduling applications. Small time-steps provide better management of feedstocks, more efficient production, and higher profit, whereas long time-horizon can leverage spot market opportunities and achieve a more comprehensive formulation. Moreover, such parameters are especially meaningful in combination with continuous rescheduling strategies. A blend scheduling case study is employed in this work, whereby the operational scheduling and economic value of the process are investigated over distinct conditions in three examples. The interplay between rescheduling optimisation and the aforementioned scheduling parameters is highlighted. The insights drawn are useful for diverse problems and scenarios, and can significantly provide further operational and economic enhancements for industrial applications.