Evaluation of agricultural residues pyrolysis under non-isothermal conditions: Thermal behaviors, kinetics, and thermodynamics

The thermal conversion characteristics, kinetics, and thermodynamics of agricultural residues, rape straw (RS) and wheat bran (WB), were investigated under non-isothermal conditions. TGA experiments showed that the pyrolysis characteristics of RS were quite different from those of WB. As reflected by the comprehensive devolatilization index, when the heating rate increased from 10 to 30 K min(-1), the pyrolysis performance of RS and WB were improved 5.27 and 5.96 times, respectively. The kinetic triplets of the main pyrolysis process of agricultural residues were calculated by the Starink method and the integral master-plots method. Kinetic analysis results indicated that the most potential kinetic models for the pyrolysis of RS and WB were D-2 and F-2.7, respectively. The thermodynamic parameters (Delta H, Delta G, and Delta S) were determined by the activated complex theory. The positive Delta H, positive Delta G, and negative Delta S at characteristic temperatures validated that the pyrolysis of agricultural residues was endothermic and non-spontaneous. (C) 2017 Elsevier Ltd. All rights reserved.