The exploration of pyrolysis characteristics, kinetics and product distribution of Bermuda grass via TG, Py-PIMS and Shuffled Complex Evolution

Abstract

The pyrolysis behaviors of biomass play an important role in understanding energy utilization. The pyrolysis characteristics, kinetics and product distribution of Bermuda grass were investigated based on thermogravimetric (TG), pyrolysis with photoionization mass spectrometry (Py-PIMS) and Shuffled Complex Evolution algorithm (SCE). The temperature range for weight loss is 450–850 K and the pyrolysis process can be classified into two regions based on the variation of activation energy, with conversion rates of 0.10–0.40 (Region Ⅰ) and 0.40–0.75 (Region Ⅱ). According to the Flynn-Wall-Ozawa (FWO) and Kissinger-Akahria-Sunose (KAS) methods, the mean activation energy values for Region Ⅰ are 126.70 kJ/mol and 124.20 kJ/mol, respectively. while the values for Region Ⅱ are 161.70 kJ/mol and 159.90 kJ/mol, respectively. Then, a three-component parallel reaction model based on the SCE algorithm was proposed and the pyrolysis kinetic parameters were optimized. The results showed the predicted values using the optimized kinetic parameters are well agreeable with experimental data, which shows that the optimized kinetic parameters and the three-component parallel reaction model may be applicable to the Bermuda grass pyrolysis. Moreover, the Py-PIMS results confirmed that the fast pyrolysis products of Bermuda grass included furan derivatives, ketones, cyclopentanones, phenols, aromatic hydrocarbons, acids and esters.