Simulación y control

Mejora en el control en cascada para reactores tubulares

Improved cascade control scheme for tubular reactors

E. Hernández–Martínez , R. Urrea y J. Alvarez–Ramirez

Universidad Autónoma Metropolitana—Iztapalapa, Apartado postal 55–534, lztapalapa, DF., 09340 México

Recibido 26 de Junio 2008
Aceptado 28 de Octubre 2008

Resumen

Los reactores tubulares son difíciles de operar debido al acoplamiento intrínsico entre los procesos de transporte, cinética no lineal y su naturaleza distribuida. Debido a las numerosas aplicaciones industriales de los reactores tubulares, el problema de monitoreo y control efectivo es de gran importancia económica y de seguridad. En este trabajo introducimos una nueva configuración del esquema de control en cascada basada en el promedio de la medición de tres temperaturas distribuidas a lo largo de la posición axial del reactor tubular (w_av). La configuración del control explota la información provista por dos sensores de temperatura adicionales localizados cerca de la alimentación y salida del reactor. La configuración con (w_av) mejora el comportamiento del esquema clásico de control en cascada frente a perturbaciones e incertidumbre de los parámetros del modelo. Mediante simulaciones numéricas se ilustra y compara el desempeño del control propuesto.

Palabras clave: control en cascada, temperatura promedio, reactor tubular.

Abstract

Tubular reactors are difficult to operate due the intricate coupling between transport processes, nonlinear chemical kinetics, and their distributed nature. However, due to numerous industrial applications for chemical tubular reactors, the problem of monitoring and controlling them effectively is of great safety and economical importance. In this work, we introduce a new cascade control scheme based on three–temperature measurement distributed along the axial position of the tubular reactor with respect to a weighted average temperature (w_av). The control configuration exploits the information provided by two additional temperatures sensor located at the feed and the output of the tubular reactor. The configuration with w_av improves the behavior of the control scheme by enhancing the disturbance and parameter's uncertainty. Numerical simulations are used to illustrate and compare the control performance.

Keywords: cascade control, average temperature, tubular reactor.

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