Metaheuristic-multiobjective optimization approach for the scheduling of multiproduct plants.

BONFILL, ANNA; MELE, FERNANDO D.; SEQUEIRA, SEBASTIÁN E.; PUIGJANER, LUIS

Barcelona, España

Congreso; 9º Congreso Mediterráneo de Ingeniería Química; 2002

Sociedad Española de Química Industrial e Ingeniería Química

This work presents a framework to deal with the scheduling problem but explicit and simultaneously considering several objectives. Thus, a set of multi-objective optimization algorithms is combined with a scheduling module, which allows the  evaluation of the objective function to assess the economic goodness of the different solutions explored. Because of the non-linearities in the problem and the integer characteristics of some of the decision variables, exact optimal solution is practically impossible to reach using standard algorithms, therefore, multi-objective versions of metaheuristic algorithms are used. Moreover, Life Cycle Assessment (LCA) criteria are included to evaluate the impact associated to the different schedule alternatives. In this way, given the recipes of each product, a temporization module calculates the timing of the entire operation schedule and the corresponding resource consumption using the sequence and raw material selection provided by the optimization algorithm. The LCA block uses the information related to raw material selection and resources consumption provided by the timing module to evaluate some insignificant environmental impact indexes. The optimization procedure offers to the decision-maker a set of Pareto optimal solutions.