Estudos térmico, termocatalítico e cinético do óleo de fritura para a obtenção de hidrocarbonetos renováveis

Abstract

The high demand in the consumption of fossil fuels makes it necessary to find alternatives for their replacement, such as fuels produced from biomass. Among biomass, vegetable oils emerge as one of the options and one of the possible conversion processes is pyrolysis. Therefore, this work proposes the use of catalytic supports zeolite H-Beta, AlSBA-15 and aluminum oxide (Al2O3), impregnated with molybdenum, as catalyst, in order to obtain renewable hydrocarbons from frying oil. The supports and catalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, scanning electron microscopy (SEM); and by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The kinetic study of frying oil, in the absence of catalysts and with Mo/HBeta, was carried out using two models with free integral methods: Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) being The activation energy (Ea) was determined with values of 190.70 and 211.64 kJ.mol-1 for the frying oil and 144.33 and 162.48 kJ.mol-1, in the respective methods. The catalysts AlSBA-15 and Al2O3 were applied in the pyrolysis reaction of frying oil in a fixed bed oven and on a bench scale, and the products were analyzed by yield under the best conditions of reaction temperature, heating rate and time of permanence, and compared by FTIR with the oil originating from the reactions in order to characterize them as the main compounds present and evaluate their use as biofuels. Although thermal studies have obtained good results in the yield of liquid fractions, between 58 and 85%, an upgrading is necessary to improve the products in terms of composition, hence the addition of catalysts, the best yields being with aluminum oxide, obtained 79% of bio-oil and in tests with AlSBA-15, 76% of bio-oil was obtained, in the latter it was observed that the porous structure of the catalyst interfered with the formation of coke, as a solid product.