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Kinetic and thermodynamic analysis of açaí seeds and insights into bio-oil optimization and composition

Pyrolysis converts biomass into other biofuels and is an alternative for residue management. This study aimed to investigate the kinetics of pyrolysis of açaí seeds and to bring insights into the slow pyrolysis of their briquettes. The thermogravimetric analysis was performed in an N2 atmosphere wit...

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Bibliographic Details
Published in:Journal of thermal analysis and calorimetry 2023-12, Vol.148 (23), p.13427-13439
Main Authors: Oliveira, P. R. S., Setter, C., Sousa, N. G., Cardoso, C. R., Trugilho, P. F., Oliveira, T. J. P.
Format: Article
Language:English
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Summary:Pyrolysis converts biomass into other biofuels and is an alternative for residue management. This study aimed to investigate the kinetics of pyrolysis of açaí seeds and to bring insights into the slow pyrolysis of their briquettes. The thermogravimetric analysis was performed in an N2 atmosphere with a final temperature of 1173 K. It tested heating rates of 2, 5, 10, 15 and 20 K min −1 . We determined the kinetic triplet using the isoconversional models of Friedman, Ozawa–Flynn–Wall, modified Coats–Redfern, Starink, and Vyazovkin, and the master plots method. In addition, slow pyrolysis occurred in a fixed-bed reactor coupled with a cooling system. The bio-oil yield was optimized via response surface methodology, and the compounds were identified with the support of gas chromatography coupled with mass spectrometry. The isoconversional model of Ozawa–Flynn–Wall showed activation energy of 165.59 kJ mol −1 , with the slightest deviation value. The average percentage deviation between theoretical and experimental master plots corresponded to second-order random nucleation. At last, the global activation energy value was 134.76 kJ mol −1 , and an Arrhenius pre-exponential factor was 1.11 1010 s −1 , with R 2  = 0.96. For slow pyrolysis, it observed an inflection point at 715 K and 11.93 K min −1 . We concluded that the second-order reaction mechanism represents the pyrolysis of the açaí seed. In addition, the bio-oil yield maximizes at milder temperatures with high heating rates or high temperatures with low heating rates. These production parameters affect the bio-oil composition.
ISSN:1388-6150
1588-2926
DOI:10.1007/s10973-023-12645-9