The kinetic analysis of the pyrolysis of agricultural residue under non-isothermal conditions

The study concerns the pyrolysis kinetics of agricultural wastes, corn straw (CS) and rice husk (RH). Thermogravimetric experiments were carried out in a thermogravimetric analyzer under inert conditions, and operated at different heating rates ranging from 5 to 40 K/min. As the increment of heating rates, the variations of characteristic parameters from the TG–DTG curves were determined. Iso-conversional Starink approach and Avrami theory were used to evaluate the kinetic parameters, including apparent activation energy and reaction order. For the range of conversion fraction investigated (20–80%), the apparent activation energy of CS initially increased from 98.715 to 148.062 kJ/mol and then decreased to 144.387 kJ/mol afterwards, whilst the apparent activation energy of RH increased gradually from 50.492 to 88.994 kJ/mol. With varied temperatures (517–697 K), the corresponding value of reaction order was increased from 0.288 and 0.359 to 0.441 and 0.692, along with a decrease to 0.306 and 0.445, respectively.