Influência do Processo Impregnação Química de Sementes de Açaí (Euterpe Oleracea) na Produção de Hidrocarbonetos Via Pirólise em Escala Piloto

In this work we investigated the hydrocarbon production via pilot scale pyrolysis of acai (Euterpe oleracea) seeds in nature and chemically impregnated with 2 mol.L-1 aqueous sodium hydrogen solution (NaOH). The experiments were performed at 450 °C, at 1.0 atm, using a Thermal Cracking pilot unit consisting of a 143 L capacity jacketed stainless steel reactor and the thermal heating source via LPG gas fired. in a burner, coupled condensation system consisting of a multi-tube hull heat exchanger with 1.30 m2 heat exchange area and water at room temperature as refrigerant. The reaction produced not condensable gases, organic liquid product (bio-oil + aqueous phase) and a solid phase (biochar). The bio-oil was characterized by physicochemical analysis of acidity index, density, dynamic viscosity, Fourier transform infrared (FT-IR) and gas chromatography coupled to mass spectrometry (GC-MS). This process aimed to evaluate the influence of impregnation on the quality and yield of the obtained bio-oils. The reaction products showed yields of 4.39% (w/w), 29.39% (w/w), 30.56% (w/w) and 35.67 (w/w) for the phases, bio-oil, aqueous, gaseous and solid, respectively, for in natura seeds, and 7.19% (w/w), 19.76% (w/w), 32.04% (w/w) and 41.00% (w/w) for the bio-oil, aqueous, gaseous and solid phases, respectively, for the impregnated seeds. It was observed that the bio-oil yield increased and the aqueous phase yield decreased with the application of impregnation process at the investigated temperature. The results found for the acidity index and dynamic viscosity of the bio-oil obtained from the impregnated seeds showed a reduction of approximately 72% and 66%, respectively, in relation to the bio-oil obtained from the fresh seeds. FTIR analyzes indicated the presence of hydrocarbons, oxygenates and biomass contaminants, as well as the reduction of transmittance intensity in the band related to carboxylic acid bonds. The GC-MS analysis showed an area percentage for hydrocarbon peaks twice as high for the bio-oil obtained via pyrolysis of NaOH impregnated seeds as compared to the hydrocarbon area percentage of the bio-oil obtained from the seeds in natura. Therefore, the application of the impregnation process with basic aqueous solutions for the lignocellulosic biomass pyrolysis process favors the formation of hydrocarbons.