Produção de hidrocarbonetos renováveis a partir da pirólise do óleo de macaúba (acrocomia aculeata) utilizando AlSBA-15, Mo/AlSBA-15, HBeta e Mo/HBeta

Abstract

In the present work, thermal and catalytic pyrolysis of macaúba oil was carried out in the presence of AlSBA-15 and HBeta catalysts and catalysts with molybdenum (Mo/AlSBA15 and Mo/HBeta), aiming at the production of renewable fuels in the range of aviation biokerosene. The AlSBA-15 catalyst was synthesized by the hydrothermal method and the commercial zeolite HBeta activated by calcination. The materials were characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Fluorescence (FRX) and Scanning Electron Microscopy coupled to Energy Dispersive Spectrometer (SEM/EDS). The AlSBA-15 catalyst was obtained with highly ordered P6mm hexagonal symmetry. Activation by calcination of HBeta did not compromise its crystalline structure. Impregnations with molybdenum metal were confirmed by FRX and EDS and did not change the structural and morphological characteristics of the supports. The thermal and kinetic studies were carried out through Thermogravimetric Analysis (TGA) at heating rates of 10, 20 and 30 °C/min, in the temperature range of 30 to 600 °C and with 10% of catalyst by weight. The biooils obtained by thermal and catalytic pyrolysis were characterized by Gas Chromatography coupled to Mass Spectrometry (GC/MS), FTIR, Acidity Index, Density, Viscosity and Moisture Content. In the thermal study, there was an indication of the efficiency of the use of catalysts in the degradation of macaúba oil through the reduction in the initial temperature of degradation. For all catalysts, there was a reduction in the activation energy of the process, especially for the mesoporous catalysts AlSBA-15 and Mo/AlSBA-15. The two kinetic models OFW and KAS were adequate for the methodology used (R² > 0.9). The physicochemical parameters of macaúba oil and its bio-oils were similar to those found in the literature. FTIR analysis confirmed the cracking of macaúba oil. In thermal pyrolysis, maximum yields of 76.59% were reached, while using HBeta and Mo/HBeta yields were 85.95% and 85.02%, respectively. Indicating that the use of catalysts can improve the pyrolysis process. The HBeta, Mo/HBeta, Mo/AlSBA-15 and AlSBA-15 catalysts produced hydrocarbons in the aviation kerosene range (C11-C16) in 90.88%, 90.45%, 71.34% and 20.35%, respectively.