Browsing by Author "Zavala, E"

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    Dynamic modelling and advanced multivariable control of conventional flotation circuits
    (PERGAMON-ELSEVIER SCIENCE LTD, 1998) Perez Correa, R; Gonzalez, G; Casali, A; Cipriano, A; Barrera, R; Zavala, E
    Expert and predictive multivariable control algorithms for a conventional cooper flotation circuit were assessed through simulations These simulations were carried out with a nonlinear dynamic model, derived from mass balances and empirical relationships, that qualitatively reproduced the dynamic behaviour of a real plant well. In order to make the simulations more realistic, they included noisy measurements, stochastic parameter variations and input disturbances. New expert algorithms were able to keep the plant operating within a pre-defined zone for long periods without complete control saturation, unlike previous expert controllers. In addition, the inclusion of constraints in a multivariable predictive algorithm verified improved control system regulation and flexibility. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.
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    Dynamic simulation and control of direct rotary dryers
    (ELSEVIER SCI LTD, 1998) Perez Correa, JR; Cubillos, F; Zavala, E; Shene, C; Alvarez, PI
    Adaptive and conventional control of a direct rotary dryer has been assessed through simulations. A dynamic model of the process was developed specifically for this purpose. The model is based on mass and energy balances and includes a drying kinetic derived from mass transfer principles. In the modelling process, ten discrete perfectly mixed elements were considered for the dryer with each containing four differential equations. A well tuned discrete PID and an adaptive algorithm were used to control the outlet solid humidity Bath controllers can regulate the controlled variable for different disturbances, although the adaptive controller is more effective. (C) 1998 Elsevier Science Ltd. All rights reserved.