Estudo da cinética de materiais complexos: modelos de reação e de distribuição de energia de ativação através de redes neurais de Hopfield

Abstract

The kinetic study of thermal decomposition of solids provides essential information about the thermal behavior of a system and its possible industrial applications. The correct determination of the kinetic triplet (activation energy, frequency factor, and parameters of the reaction model) depends, above all, on the choice of the most appropriate kinetic model to describe the system. To evaluate the green petroleum coke and sewage sludge, three kinetic analysis methods were used: isoconversional analysis, Cai-Liu empirical model, and distribution activation energy model (DAEM). The last two were optimized by Hopfield's neural network (HNN). The determination of the activation energy distribution, using the HNN algorithm, was performed for the first time in this work and simulated data were used to validate the computational code developed. The green petroleum coke was better adjusted using the Cai-Liu equation, which points to a reaction with the contribution of Avrami-Erofeev and first-order models. The kinetic parameters that best represent the coke decomposition are k0=3,1009e6 min^-1 e E0=112,51 kJ/mol. The sewage sludge presented multi-stage kinetics represented by a 5-DAEM process. The kinetic parameters that best represent the sludge decomposition are k0=1,26e10 min^-1 e E0=83,984; 111,328; 119,140; 130,859 e 146,375 kJ/mol.