Effect of Microwave Pretreatment on Pyrolysis of Chili Straw : Thermodynamics, Activation Energy, and Solid Reaction Mechanism

In this work, chili straw (CS) is pretreated by microwave at 250W, 406W, 567W, and 700W. The pyrolysis characteristics , kinetics, thermodynamic parameters, and solid reaction mechanism are investigated. The maximum weight loss rate increases from -24.72%/min at P0 to -28.01%/min at P700 after microwave pretreatment, and the residual mass decreases from 31.81% at P0 to 26.71% at P700. In addition, microwave pretreatment leads to a decrease in activation energy, ∆H, and ∆G at the end of the pyrolysis (α>0.7). The solid reaction mechanism of CS pyrolysis is revealed by the Z-master plots method, with unpretreated CS conforming to P2, D4, F3/2, and F3, respectively. Microwave pretreatment changes the solid reaction mechanism mainly in the third stage, when α=0.8, the mechanism function changes from f(α)=(1-α) 3 at P0 to f(α)=(1-α) at P700, and the number of reaction order is reduced, which is profitable for CS pyrolysis