RemoÃÃo de tiofeno utilizando adsorventes preparados por mistura fÃsica

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The need for cleaner fuels has increased that the studies aimed at reducing levels of sulfur in gasoline. The presence of sulfur compounds in fractions of oil is highly undesirable because it results in corrosion and environmental pollution. The hydrodesulfurization is the main process responsible for removing sulfur from most of the fuel industry of oil refining. The biggest problem of hydrodesulfurization is its limitation. The consumption of hydrogen, energy and catalysts of cobalt and molybdenum, lead time, high cost and increase the severity of the process, which directly influences the octane of fuel. New desulphurisation processes have been developed and appears promising for adsorption process to remove sulfur compounds present in diesel and gasoline after the HDS process. In this paper we present a study of the removal of sulfur in the mixture using isooctano/ tiofeno adsorbents prepared by physical mixing. The starting materials for the preparation of these adsorbents were mixed oxides of zinc and nickel synthesized by the polymeric precursor method and mechanochemical the Nay zeolite and -Al2O3. These materials were characterized by X-ray diffraction (XRD) measurement of surface area for adsorption of N2 (BET), espectrofometria, atomic absorption (AA), thermogravimetric analysis (TG) and scanning electron microscopy (SEM). Results indicated that the mixed oxides showed two crystalline phases with similar textural characteristics, contents of metal next to the desired morphology and plate (Pechini) and spherical clusters (mechanochemical). Adsorbents prepared for the physical mixing method did not influence the crystallinity, there was a decrease of specific surface area and loss of mass due to removal of adsorbed water. The images of SEM showed clusters of particles form in spheres of various sizes. The adsorption of thiophene in iso-octane was measured by kinetic study in finite bath system and balance. The results showed higher adsorption capacities for PEC-Al2O3 and MECAl2O3. For continuation of the tests was selected the MEC-Al2O3 adsorbent, since the technique is cheaper and mechanochemical fast as the polymeric precursor, and the opportunity to prepare in large quantities. The experimental data of equilibrium isotherms were fitted to the Langmuir- Freundlich model with n = 2.67 for the MEC-Al2O3 adsorbent with Keq = 2,4827.10-6 and qs = 2.79 mg S / g of adsorbent . The kinetic model of Langmuir-Freundlich adequately represented the experimental data.

ASSUNTO(S)

engenharia quimica combustÃveis adsorÃÃo mixed oxides Ãxidos mistos adsorption thiophene tiofeno fuel

ACESSO AO ARTIGO

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