Real-Time Optimization of Raw Materials in the Cement Industry

Abstract Raw material prehomogenization by using big stockpiles is widely used in the cement industry. An attractive alternative of raw material mixing is obtained by the use of an efficient control strategy together with a continuously operating homogenization silo. The benefits of the latter system is that large investments in homogenization equipment can be avoided, on the other hand more emphasis must be put into the control system. Some commercial systems of this type are available today. The control system structure in theese systems usually consists of two main disiplines, a quality control system and an optimization procedure. The first problem has been widely discussed in the litterature while the real-time optimization problem has not been given much attention. Explicitely the latter problem is to obtain the least expensive and if possible the least sensitive mix of the raw materials that satisfies the quality requirements of the raw meal. The optimization problem has to be solved under incomplete and stochastic information of the different raw material component concent rations, and furthermore in real time. Some methods, algorithms and problems in solving the real-time optimization problem are viewed in the actual paper.