Redução do teor de enxofre de gasolinas sintéticas através do processo de adsorção utilizando peneiras mesoporosas MCM-41.

Abstract

The presence of sulfur containing compounds in the feeds of crude oil in some petroleum fractions obtained by their processing and the increasing environmental constraints have demanded the search for new technologies to reduce the sulfur contents in the fuels produced by these refining processes. The conventional hydrotreating technologies used at present for this purpose involve high costs, complex facilities and uses sophisticated catalysts. The national and international projections for the sulfur contents in transportation fuels, are going to be at the levels close of zero in short, medium and long period depending on the place. These levels represent a big reduction and a will be attained with much difficulty with the conventional technology, because it needs a deep desulfurization, that means a more than 95% of conversion. Recently, proposals have appeared for the additional removal of sulfur contents in the gasoline through the processes of adsorption. Such processes are less complex than the conventional hydrotreating and are based on the ability of a specific adsorvente to selectively adsorb sulfur compound as tiois (mercaptans), tiofenos and benzotiofenos which are present in the refinery streams. In the present study MCM-41 was used as adsorbente material and a cyclohexene/mercaptan as synthetic fuel. The MCM-41 was synthesized at ambient temperature and characterized by X-ray powder difraction, scanning electron Microscopy and N2 Adsorption-desorption techniques. After obtaining the desired MCM-41, kinetic tests were carried out in system of a finite bath with the objective of studying the reduction of the sulfur contents of the synthetic gasoline. The results showed a low relationship for adsorbente quantity / treated solution volume, when compared with obtained values observed for system of natural zeolite as adsorbente. On the other hand the need of activation of MCM-41 by inserting metallic sites is suggested because during the adsorptive process the mercaptan as well as the cyclohexene were adsorbed.