Simulação do processo de adoçamento do tratamento primário do gás natural em plataformas de extração offshore

Abstract

The natural gas extracted from oil wells has in its composition molecules with acid characteristics considered contaminants, such as hydrogen sulfide (H2S) and carbon dioxide (CO2) that need to be separated and removed from the mainstream. The main reason why it is important to remove H2S from the natural gas stream is its toxicity, while CO2: corrosiveness. The objective of this work was to study the sweetening step of the primary treatment of natural gas using an aqueous amine solution as an absorber and an absorption column. Furthermore, another objective was to evaluate the influence of the absorber column operating pressure on the separation of these contaminants from the non­treated stream. The simulations were performed on the commercial simulator AVEVA™ PRO/II™, version 2021. The simulated plant was composed of an absorber column, a regeneration column, a Flash vessel, and heat exchangers. The pressure in the absorption column was varied from 2 to 10 atm to study the effects of this variable on the absorption of acid gases. The study showed that the absorption column was able to remove acid contaminants from the natural gas stream under all simulated conditions, and that absorption is little affected by varying the operating pressure. Also, regeneration of the amine solution occurred without large material losses and that the simulated process with recycle is difficult to converge.