Impact of torrefaction on thermal behavior of wheat straw and groundnut stalk biomass: Kinetic and thermodynamic study

Abstract

This study investigates the physicochemical behavior of Wheat Straw and Groundnut Stalk biomass and its impact on the thermal behavior during torrefaction process. The torrefaction was experimentally investigated by thermogravimetric analysis (TGA) at five isothermal heating rates of 20, 30, 40 and 50 °C/min. Results revealed that during the torrefaction process, significant fraction of hemicellulose and volatile content reduces that improves the high heating value. The results indicated that torrefaction treatment improved the fuel properties with elevated torrefaction temperature, including the lower volatile content, higher carbon content, and higher heating value. Kinetic parameter analysis indicated that the Ozawa–Flynn–Wall and Starink model were significant in calculating the activation energy, and the average activation energy was 240 kJ/mol and 238 kJ/mol (Wheat Stalk and torrified wheat Stalk) 127 kJ/mol and 129 kJ/mol (Groundnut Stalk and torrified Groundnut Stalk). An excellent linear relationship between lnA and Eα was observed, indicating that the compensation effect existed between the Eα and lnA during torrification. These results provide important basic data support for the thermochemical conversion of cornstalk to energy and chemicals.