An industrial application of multivariable linear quadratic control to a cement mill circuit

There are a variety of control strategies that one may consider for cement mill circuit control and often several methods for implementing each strategy. Ideally, the control strategy selected and methodology used in it's implementation should not only optimize circuit performance in terms of productivity but also be able to optimize quality. A linear quadratic multivariable controller has been applied to milling circuits and these goals successfully accomplished. The results are a stable circuit with mill and separator optimized, producing a consistent quality product of a predictable fineness. This enables one to use cement quality as the single circuit control set point.