Developing an integrated model of an aluminium smelter incorporating sub-models with different time bases and levels of aggregation

In this paper an integrated production model of an aluminium smelter is discussed. The core model, i.e., the model involving the largest time base and highest level of aggregation of the production process, is a nonlinear bilevel programming problem. A number of smaller intermediate product modelling type mixed integer sub-models involving smaller time bases and lower levels of aggregation of the production process are important components of the overall integrated production model. It is shown that in order for the core integrated model of the smelter to be able to be specified with respect to some capacities, etc., and for the results of the integrated model to be implemented, these sub-models are necessary.