A Dynamic Scheduling Framework for Byproduct Gas System Combining Expert Knowledge and Production Plan

Effective scheduling for byproduct gas systems of steel industry is becoming increasingly vital for maintaining their safe operating and improving energy utilization. Considering that the existing studies failed to capture the dynamic changes in the production environment, a novel dynamic scheduling framework is proposed that seamingly integrates expert knowledge with a dynamic programming process. Given the phase characteristics of the steelmaking processes, data series are first partitioned into information granules based on the production plan to form the knowledge-based initial policies. To achieve dynamic scheduling process, a two-stage value function approximation method is proposed, where in the first stage one learns an event-driven Q-function by the fuzzy rule-based states, and then an action fitting strategy is developed for evaluating continuous actions. Considering the difficulties of establishing a mechanism-based model, the state transition process is described by a granular prediction model to simulate taking actions. On their basis, a dynamic compensation for the initial policies is finally achieved. A number of comparative experiments are conducted by utilizing the practical data coming from a steel plant. The results show that the proposed method can deliver effective solutions for long-term scheduling scenarios. Note to Practitioners—Given that the steelmaking process is a discontinuous one and the byproduct gas system can hardly be described by a physical or mechanism-based model, its energy scheduling works is usually performed by manual approach or using static optimization methods, which would lead to low accuracy and a waste of energy. Since a large number of real-time data had been accumulated by the SCADA system implemented in most steel plants, a data-driven dynamic scheduling approach is proposed in this study. The proposed method takes advantages of the expert knowledge and production plan data, and produces dynamic scheduling solutions by utilizing an actor-critic learning process. The application system on the basis of the proposed method can adapt to different scenarios and ensure long-term safety operations of the gas tanks. Furthermore, since there may be missing data or outliners in the acquired data collected by the SCADA onsite, it is necessary to perform data imputation and filtering methods to guarantee the data integrity and reliability. This study avoids the redundant introduction of such preliminary preprocessing methods for the sample data.