Investigation of tobacco straw pyrolysis: Three-parallel Gaussian reaction modeling, products analysis and ANN application

Abstract

The pyrolysis behaviors, reaction kinetics, thermodynamic parameters, and reaction mechanism models of tobacco straw (TOS) were determined using a three-parallel Gaussian reaction model. The apparent activation energies for the pyrolysis of pseudo cellulose (P1-HE), hemicellulose (P2-CE) and lignin (P3-LI) pyrolysis were determined using the Ozawa-Flynn-Wall, Kissinger-Akahira-Sunose, Starink, Tang, and Distributed Activation Energy Model model-free methods. The average apparent activation energies for P1-HE, P2-CE, and P3-LI were 153.67, 178.53, and 190.45 kJ/mol, respectively. The pyrolysis process was well described by the dimensional, order, diffusional, and power law reaction mechanism models. Twelve types of pyrolysis products, including benzenes, acids, phenols, furans, indoles, pyridines, hydrocarbons, pyrroles, ketones, alcohols, quinolines, and aldehydes, were identified as the main pyrolysis products. Combining Raman and SEM analyses, pyrolyzed biochar at 800 °C was suitable as a catalyst or catalyst carrier. An artificial neural network (ANN) was utilized to predict the thermal degradation behaviors of TOS pyrolysis, and the hyperparameters of the activation function were optimized. The best ANN model structure was ANN (5 *11 *1). This study provided theoretical and practical guidance for further rational utilization of TOS waste.