Case Metal refining processes
In metal refining the aim is to obtain the specification of one or several chemical components within product specifications, while at the same time obtain a product temperature within a preferred narrow window within a defined margin above the melting temperature. At the same time, production amounts should be optimized, at a lowest possible cost.
In some refining processes, this could be done by batch-to-batch optimizing of fines additions and optimized flow profiles of refining gases. In batch refining processes where some chemical analyses and measurements are available during the refining, a full Model Predictive Controller (MPC) can be implemented as a monitoring and operation support system, as well as closed loop control.
End point prediction of product quality and production yields, as well as optimized economical margins are key variables for the MPC to calculate and optimize on.
During the life time of the refining equipment (ladles, converters, gas nozzles, etc) are worn, or material grow onto them, causing the refining to become less optimal. These changes are often slowly evolving until the equipment is so worn or damaged, that it needs to be replaced. Adaptive techniques using estimators are used to identify this change in behviour. Having updated parameters in the model, ensures that the optimization is still valid even if the equipment characteristics may change.