Metodologia para modelagem e controle amplo aplicado a um circuito simulado de moagem de bolas

Abstract

Modelling and plantwide control design applied to a simulated ball mill circuit for iron ore are proposed in this dissertation. At the modelling step, King’s model and Plitt’s model are used for ball mill and for cyclones, respectively, and dynamic frequency models for inputs-outputs process variables are identified. The potential for applying apex diameter adjustment as an alternative input variable to optimize the classification process is evaluated in the simulated circuit. The control structure is result of plantwide control design technique based on top-down analysis and bottom-up project. Direct synthesis method based on set-point responses and disturbance rejection are used for designing and tuning Proportional-Integral-Derivative controllers. The performance of the control structure is assessed by the index integral of the absolute magnitude of the error facing set-point changes for product size specification, ball mil variations and number of cyclones running. The multiloop control structure applied to the circuit - in the dynamic simulation environment - presents satisfactory results for all evaluated scenarios, indicating potential for real implementation, including the apex diameter variation as manipulated variable. This simulated control structure must be validated in industrial application.