Estudo de catalisadores de níquel suportado na reação de hidrodesoxigenação (HDO) de guaiacol

Abstract

Environmental concern is causing industries to intensify their search for more efficient and economical alternative chemical processes. One solution to the environmental problem is to use renewable energy, which is increasingly present in the industrial atmosphere. Renewable fuels, such as bio-oil, are produced from the fast pyrolysis process of lignocellulosic biomass. The bio-oil is formed by several oxygenated compounds and presents limited application as fuel due to its chemical and physicochemical properties, which are conferred by the high oxygen content in its composition. In order to use the bio-oil as fuel in the combustion engines, it is necessary to carry out the catalytic hydrodeoxygenation process, where the removal of the oxygen is achieved under an atmosphere of hydrogen in the presence of a catalyst. In this work, before performing the reactions, the characterization of the catalysts (5% Ni/SiO2, 5% Ni/Nb2O5 and 5% Ni/Al2O3) was carried out by using the X-Ray Diffraction (XRD), the calibration curve of the model molecule (guaiacol) was made and then the catalytic tests were accomplished. In the XRD analysis, it was verified that the diffractogram of the 5% Ni/SiO2 catalyst showed peaks related to the amorphous phase of silica, as well as peaks representing Ni0 and NiO. For the 5% Ni/Nb2O5 catalyst only the peaks related to the support phase were obtained and the same occurred for the 5% Ni/Al2O3 catalyst. The catalytic test was carried out with the three catalysts and the supported one on silica (SiO2) presented higher deactivation, probably due to sintering or coke formation. In contrast, the alumina-supported catalyst (Al2O3) was shown to perform better compared to the others.