Cinética de pirólise para o sorgo lignocelulósico: análise de dados termogravimétricos para aplicação do modelo de Friedman

Renewable resources are alternatives to fossil fuels and pyrolysis is identified as a process for the generation of biofuel products. The lignocellulosic sorghum is a cereal produced in brazil and it presents several applications, such as the production of second-generation ethanol. The present work aimed to study the slow pyrolysis of lignocellulosic sorghum, the biomass was characterized by means of proximate, ultimate, composition and carbohydrate analyzes. Thermogravimetric analyzes were performed with heating rates between 5 and 25 K min^-1 and with N₂ atmosphere. The Friedman model allows obtaining the kinetic parameters of biomass decomposition and is widely used due to its simplicity and precision; however, since it is sensitive to experimental noise, an algorithm was developed for the calculation of kinetic parameters for the slow pyrolysis of this biomass, enabling an accurate analysis of the experimental data. The activation energy found by the proposed methodology was 122.65 ± 19.24 kJ mol^-1, with determination coefficients above 0.97. The comparison between experimental and theoretical data presented deviation values of 0.934%, 3.408% and 1.101% for heating rates of 5, 10 and 15 K min^-1, respectively, showing the accuracy for the determined kinetic parameters.

Keywords:
activation energy; fibrous sorghum; pyrolysis; smoothing; Friedman model