Processos termocatalíticos aplicados ao aproveitamento sustentável dos resíduos agroindustriais da palha da cana-deaçúcar para produção de energia alternativa

Abstract

Due to the large agricultural production Brazil has a considerable amount of agricultural and agroindustrial residues whose bioprocessing can be of great economic and social interest. The use of sugarcane straw for energy production appears as an alternative use of an agricultural residue. The application of technologies that can add value to sugarcane straw are of great relevance. In this context, for this study, the thermochemical pyrolysis process was applied to sugarcane straw biomass in a fixed-bed pyrolysis reactor. Biomass was characterized by immediate and instrumental analysis (Elementary Analysis, C-200 Colorimetric Pump and Thermogravimetric Analysis). A simulated pyrolysis study by thermogravimetric analysis was performed to evaluate the thermal stability and degradation of organic matter in an inert atmosphere. The influence of the variables: final temperature (450 °C), heating rate (10 °C/min at 30 °C/min) and pyrolysis time (120 min) were studied in the thermochemical pyrolysis process. The bio-oil obtained was characterized by instrumental techniques. The maximum yield of the bio-oil was on the order of 39.50% (m/m) obtained in the heating rate condition of 10 °C/min. The lowest yield of the solid fraction was in the order of 43.75% (m/m) at the heating rate condition of 30 °C/min. The bio-oil had the following characteristics: pH (1.15 for heating rate 10 °C/min and 1.11 for heating rate 30 °C/min), density (1.07 g.cm-3 for rate heating rate 10 ° C/min and 1.09 g.cm-3 and for heating rate 30 °C/min), viscosity (2.23 mm.s-1 for heating rate 10 °C/min and 2,18 mm2.s-1 for heating rate 30 °C/min), calorific value (11.98 to 15.84 MJ.kg-1) and corrosivity (1b for both heating rates). The results of the thermogravimetric analysis showed that the bio-oil contains a considerable amount of light compounds with a boiling point <350 °C, corresponding to 71.68% of the mass of the bio-oil. The application of thermo-catalytic process to sugarcane straw to obtain biofuels is shown as an alternative to recover and add value to this residue, transforming it into raw material, as well as, reducing the environmental impacts caused by the agricultural and agroindustrial residues of sugarcane straw.