RemoÃÃo de Enxofre da Gasolina em Coluna de Leito Fixo, com uso de Adsorventes ZeolÃticos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

The emission of poisons like SOx and hydrocarbons from automotives vehicles is at the moment one of the major sources of atmospheric pollution. The SOx, for instance, is responsible for corrosion in cars, industrial facilities and acid rains. So, during the last years the environmental protection agencies have reduce drastically the levels of permitted emission of pollutants from fuels, making the specifications very strict. The known main sulfur removal process in oil refineries is hydrodesulfurization but it aggregates high costs to the products. An alternative process may be its removal by adsorption, as it is a process of comparatively lower costs and selective to the adsorbents for different separation processes. In this work adsorbents from NaY zeolite were prepared by ion exchange with ZnCl2 under agitation and dried in an oven at 120ÂC for one hour. At the end of the operation one sample had 0,5% and the other 5,05 % of ZnO incorporated to the zeolite. They were then pelletized with the addition of 0,5% of graphite and calcinated at the same conditions. These adsorbents were characterized by atomic adsorption spectrometry, X-ray diffraction (XRD) and its surface area was measured by BET. A propanethiol mixture with ciclohexene was used as a representative oil ample for the dynamic adsorption study in a fixed bed column at laboratory scale. Besides the prepared zeolites, Zn(0,5%)Y and Zn(5%)Y a well known commercial adsorbent, Selexsorb, was also used. The removal process was accompanies via the sulfur analyzer EDX-700 Model RayNY from Shimadzu. The dynamic adsorption data of propanethiol in ciclohexene obtained for the three adsorbents were adjusted to a mathematical model which involved the convection effects, axial dispersion and external mass transfer. The solution of this model was obtained by apllying finite differences. The average values of the coefficients were Dax=2 x 10-4 cm2 min-1 e KLS = 9x10â6 cm min-1

ASSUNTO(S)

leito fixo fixed bed seolite enxofre engenharia quimica adsorÃÃo zeÃlita sulfur adsorption

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