Estudo da conversão térmica e termocatalítica para pirólise de óleo de licuri (Syagrus Coronata) utilizando KIT-6 funcionalizado com níquel e molibidênio

Abstract

The use of fuels derived from fossil sources has caused major global challenges, and the development of research in search of renewable energy resources is relevant. Therefore, the present work aims to evaluate the potential of licuri oil (Syagrus Coronata) for pyrolysis based on its thermal and thermocatalytic conversion using nickel and molybdenum catalysts supported on KIT-6. The catalysts were characterized by X-Ray Diffractometry (XRD), Thermogravimetric Analysis (TGA), Fourier Transform InfraRed spectroscopy (FTIR), Scanning Electron Microscopy (SEM/EDS) and X‐Ray Fluorescence (XRF). From the characterization of the materials, it was verified that the KIT-6 presented a well-ordered structure and that it remained unchanged after the impregnation of the metals to the support. A thermal and thermocatalytic study was carried out using thermogravimetric data obtained at heating rates of 10, 20, 30 and 40 °C/min, where a greater conversion was noted when the sample was heated more slowly. Through the kinetic study applying the Ozawa-Flynn-Wall (OFW) and Kissinger-Akahira-Sunose (KAS) model, it was verified based on the values of the correlation coefficient (R²) that the KAS model best suits the process of thermal and thermocatalytic degradation of licuri oil. The assays were labeled in the OLKX format, where "OL" is the acronym for licuri oil, "K" refers to the KIT-6 material, and "X" represents the metals that were grafted onto the support. Thus, OL, OLK, OLKNi, OLKMo, and OLKNiMo exhibited average apparent activation energies (Ea) of 75.63; 102.49; 78.11; 85.57; and 122.11 kJ/mol, respectively. These results suggest that complex reactions occurred in the presence of the catalysts, leading to an increase in Ea values compared to the thermal assay of the oil. When analyzing the thermodynamic parameters, it was observed that ΔH and ΔG presented positive values, indicating that the thermal and thermocatalytic degradation process of licuri oil is endothermic and does not occur spontaneously. Furthermore, negative values of ΔS suggest that the biomass is close to its thermodynamic equilibrium. Therefore, the results of this study suggest that licuri oil has the potential to be used as a raw material for pyrolysis.