An Application of MILP-based Block Planning in the Chemical Industry

Production processes in the chemical industry often consist of an initial stage in which a basic chemical product is produced and a subsequent stage which produces the final product variants according to demand forecasts or customer orders. Typically, a filling and packaging process is integrated into this final production stage. For scheduling the production and packaging activities a mixed-integer linear programming (MILP) model is proposed which is based on the definition of setup families and the production of product variants in a pre-defined sequence. The model determines the size and the time phasing of the individual production lots. In contrast to conventional lot-sizing and scheduling models, the proposed optimization model is based on a continuous representation of time.