Análise técnica e de viabilidade de um processo de pirólise por microondas

Abstract

This study investigated the pyrolysis processes of the jatobá fruit peel. First was made the proximate analysis of biomass; from the proximate analysis results, the moisture, ash, volatile matter, and fixed carbon content were determined. From these values, the elemental composition of the jatobá fruit peel was determined using the Parikh, Shen, and Nhuchhen methodologies, in addition to the arithmetic mean of the three methodologies. From the elemental composition and characterization of the jatobá fruit peel, the atomic classification of the jatobá fruit peel was performed, and the atomic ratio was calculated using the van Krevelen diagram. The moisture content was 8.67% ± 0.09%, the ash content was 1.52% ± 0.01% on a dry basis, the volatile content was 80.71% ± 2.63% on a dry basis, and the fixed carbon fraction was 17.77% ± 2.63%. From the average of the three methodologies, it was possible to determine that the carbon content was 48.27% ± 0.46%, the hydrogen content was 5.91% ± 0.01%, and the oxygen content was 43.86% ± 0.34%. From the micropyrolysis tests, it was observed that alkaline catalysts such as potassium hydroxide and calcium oxide presented the best results, since these compounds favored the formation of hydrocarbons, which was explained by the high hydrocarbon content in the volatiles. Tests conducted with calcium oxide at 650 °C showed a hydrocarbon content in the volatiles of 15.0%, while tests conducted at 650 °C using potassium hydroxide showed a hydrocarbon content in the volatiles of 17.1%. It was also observed that the absence of higher temperatures favors hydrocarbon formation. Experiments involving microwave-assisted pyrolysis were performed using particles with diameters between 0.250 mm and 0.355 mm and particles with diameters between 0.106 mm and 0.180 mm; larger particles favored charcoal formation, while smaller particles favored bio-oil formation. Long duration experiments and temperatures between 550 °C and 620 °C are favorable to produce bio-oil. While temperatures between 451 °C and 550 °C are favorable for producing charcoal. Scanning electron microscopy images showed that the charcoal is much more porous and has a more irregular surface than the original biomass, indicating a larger surface area compared to the original biomass.