Modelagem matemática de um sistema tubulação-separador sob regime de fluxo com golfadas e controle de nível considerando um algoritmo de erro-quadrático.

Abstract

This work presents the development of a dynamic model for a pipeline-separator system under slug flow. The model has 5 (five) nonlinear ordinary difierential equations, and has been obtained by coupling both the simplified dynamic model of Storkaas for a system pipeline, in conditions of slug flow, and a model for a bi-phase horizontal cylindrical separator. Currently, feedback control strategies are considered as a promising solution to handle the slug flow. In this context, the new model is an appropriate environment for simulated application of different feedback control strategies to the probíem of the slug in oil industries. The model proposed allows for applying such strategies to the oil or gas output valve separator (that is, to study of the effects of the slug) as well as to the top riser valve, or yet to more than valve símuítaneously, in the integrated system in other words (that is, to investigate the slug causes). Also this work studies the properties and applications of the nonlinear controller denominated error-squared controller. Based on the Lyapunov stability theory, theorems for computation of the limits of the controller nonlinear gain are presented. Next, the effects of using the error-squared controller with either the conventional levei control or the band control strategies are compared as appíied to a separator under slug flow. In these studies the dynamic model for a pipeline-separator was used. Analysis of simulation results shows that the model proposed is consistent in representing the flow regime with slug and that it can be satisíáctorily appíied to investigate the effects caused by the slug in the separator output flow. Also, it was verified that the use of the error-squared controller together with the band control strategy resulted in reduction of oscillations in the output flow, when compared to the use of PI controller.