Comprehensive kinetic study of Imperata Cylindrica pyrolysis via Asym2sig deconvolution and combined kinetics

Abstract

Abstract This study examined the non-isothermal kinetics of the slow pyrolysis of Imperata Cylindrica (IC). Pyrolysis conditions were developed under the pure N2 flow and non-isothermal conditions at the heating rates of 2.5, 5, 10, and 17.5\u2009K/min and over the temperature range of 303 – 1173\u2009K. The IC pyrolysis profiles could be identified into three parallel reactions, each of which corresponded to pseudo-hemicelluloses (P-Hem), pseudo-cellulose (P-Cell), and pseudo-lignin (P-Lig) decomposition. A systematic kinetic study of the pyrolysis of IC via thermogravimetric analysis (TGA) deconvolution using Asymmetric Double Sigmoidal (Asym2sig), Friedman differential iso-conversional and combined kinetics of biomass pseudo-components was carried out. The kinetics parameters of pseudo components fitted well with the pyrolysis experimental data for all the heating rates. Differential master-plots showed that the reaction mechanisms for pseudo hemicellulose (P-Hem) and pseudo cellulose (P-Cell) were diffusional and order based, and high order based (3rd order) for the pseudo lignin (P-Lig). Mechanism of P-Hem, P-Cell and P-Lig could be further reconstructed to Sestak and Berggren model of f α = α - 0.9875 1 - α 1.325 - l n \u2061 ( 1 - α ) 0.0209 , f α = α 0.3313 1 - α 1.4731 - l n \u2061 ( 1 - α ) 0 . 0215 and f α = α - 2.9551 1 - α 2.7642 - l n \u2061 ( 1 - α ) 0.0074 , respectively. The combined kinetic reported the activation energies of pseudo-components were as 194.709\u2009kJ/mol, 179.968\u2009kJ/mol and 219.226\u2009kJ/mol for P-Hem, P-Cell and P-Lig, respectively.