doctoralThesis
Síntese e caracterização de aluminofosfato impregnado com molibdênio/zinco visando a dessulfurização por adsorção
Fecha
2011-10-27Registro en:
GOMES, Kalyanne Keyly Pereira. Síntese e caracterização de aluminofosfato impregnado
com molibdênio/zinco visando a dessulfurização por adsorção. 2011. 125 f. Tese (Doutorado em Pesquisa e Desenvolvimento de Tecnologias Regionais) - Universidade Federal do Rio Grande do Norte, Natal, 2011.
Autor
Gomes, Kalyanne Keyly Pereira
Resumen
Discussions about pollution caused by vehicles emission are old and have been developed
along the years. The search for cleaner technologies and frequent weather alterations have
been inducing industries and government organizations to impose limits much more rigorous
to the contaminant content in fuels, which have an direct impact in atmospheric emissions.
Nowadays, the quality of fuels, in relation to the sulfur content, is carried out through the
process of hydrodesulfurization. Adsorption processes also represent an interesting alternative
route to the removal of sulfur content. Both processes are simpler and operate to atmospheric
temperatures and pressures. This work studies the synthesis and characterization of
aluminophosphate impregnate with zinc, molybdenum or both, and its application in the
sulfur removal from the gasoline through the adsorption process, using a pattern gasoline
containing isooctane and thiophene. The adsorbents were characterized by x-ray diffraction,
differential thermal analysis (DTG), x-ray fluorescence and scanning electron microscopy
(SEM). The specific area, volume and pore diameter were determined by BET (Brunauer-
Emmet-Teller) and the t-plot method. The sulfur was quantified by elementary analysis using
ANTEK 9000 NS. The adsorption process was evaluated as function of the temperature
variation and initial sulfur content through the adsorption isotherm and its thermodynamic
parameters. The parameters of entropy (ΔS), enthalpy variation (ΔH) and free Gibbs energy
(ΔG) were calculated through the graph ln(Kd) versus 1/T. Langmuir, Freundlich and
Langmuir-Freundlich models were adjusted to the experimental data, and the last one had
presented better results. The thermodynamic tests were accomplished in different
temperatures, such as 30, 40 and 50ºC, where it was concluded the adsorption process is
spontaneous and exothermic. The kinetic of adsorption was studied by 24 h and it showed that
the capability adsorption to the adsorbents studied respect the following order: MoZnPO >
MoPO > ZnPO > AlPO. The maximum adsorption capacity was 4.91 mg/g for MoZnPO with
an adsorption efficiency of 49%.