Síntese de bio-hidrocarbonetos via desoxigenação de óleos de soja e macaúba utilizando catalisador de nióbio sob pressão atmosférica

Abstract

This dissertation aims to synthesize bio-hydrocarbons from the deoxygenation of soybean oils and macauba pulp using niobium as a catalyst, under atmospheric pressure, for the production of drop-in biofuels, which are free of oxygen in its structure and considered the most efficient biofuels and demanded for their characteristics similar to the properties of fossil derivatives. The used oils were characterized by determining acidity, humidity, fatty acid composition, thermogravimetric curve (TG-DTG), and infrared spectrum (FTIR-ATR). The catalyst was characterized by X-ray diffraction spectrometry, thermal analysis (TG-DTG), nitrogen gas adsorption analysis, programmed ammonia temperature desorption (TPD-NH3), and pyridine adsorption. The catalytic tests for the study of the deoxygenation reactions were made by varying the time (2.5 to 5.0h), temperature (250 to 400 ºC), and proportion of catalyst (0 to 20 %). The products were characterized using gas chromatography coupled to mass spectrometry (GC-MS) and spectroscopy in the medium infrared region (FTIRATR). The calorific values of the most relevant products were determined, being 43.32 and 44.62 MJ kg -1 . The best results were obtained for the process using 20 % by mass of catalyst, temperature of 350 ºC and a reaction time of 2.5 hours, in a batch process with high yields (85 %) of bio hydrocarbons, mainly in the range of bio-jet fuel (59 %), using macauba pulp oil and green diesel (67 %), for soybean oil. Catalyst reuse tests were performed indicating good stability of up to five cycles tested. This route proved to be very promising for industrial use due to the high yields in a low processing time.