Sistema fuzzy multivariável aplicado ao controle da composição do gás liquefeito de petróleo

Abstract

In the present work, artificial intelligence techniques were applied in a simulated natural gas processing plant, composed of two distillation columns, a deethanizer column and a debutanizer column. In this process, the background product of the deethanizer, known as LGN, is supplied to the debranching column, where it is fractionated. The lighter components are evaporated giving rise to LPG (Liquefied Petroleum Gas), while the heavier fractions, denominated of C5+, remain in the liquid state. Ideally, LPG is composed only of butane and propane, but in practice this is not the case, since contaminants such as pentane and ethane are always present. In this work it is proposed to simultaneously regulate the amount of pentane and ethane in the LPG composition by means of the dynamic generation of set points (SP) for the present controller’s layer of the instrumentation known as regulatory control. For this, a multivariate fuzzy system is used that will adjust the values of these SPs, from the comparison of the molar fraction of pentane and ethane present at the exit of the plant (LPG) and its desired quantities. The columns were simulated in the HYSYS R chemical process simulation software designed with real characteristics of the columns present in the Natural Gas Processing Unit, located in the municipality of Guamaré-RN.