Environmentally friendly scheduling for primary steelmaking processes

Abstract

In this study, a novel continuous time formulation for scheduling of primary steelmaking process is proposed. The model is tailored to accommodate batch and continuous operation modes where the scheduling problems in steelmaking industry have been focused. Several examples are provided to illustrate the capabilities of the proposed mathematical models, and it is extended to a large size problem of the primary steelmaking process containing 14 facilities and 25 batches. Also, based on the proposed scheduling model, a systematic methodology for incorporating environmental considerations in the scheduling of primary steelmaking processes is presented. In order to consider environmental impacts, a Life Cycle Assessment (LCA) methodology is used. The methodology embeds principles of LCA within a general multi-objective formulation for the scheduling of primary steelmaking processes. The objectives of the formulated multiobjective MILP model are to maximize the profit, minimize the makespan, and minimize environmental impacts. The $\epsilon$-constraint method is applied in order to solve the multiobjective optimization problem and generate its Pareto solution. The optimization solutions show trade-offs between economic and environmental aspects. According to the Pareto set, the decision maker can select any schedule strategy by his preference.