Characterization-, energy potential-, pyrolysis kinetics-, and non-isothermal thermogravimetric – study of raw and torrefied Moringa husk

Abstract

ABSTRACT About 0.384 million tonnes per year of unutilized Moringa husk (MH) is generated worldwide, which can produce a substantial amount of py-oil through pyrolysis. Based on the above fact, the present has been planned to study the chemical characterization, exergy analysis, and pyrolysis kinetics of raw and torrefied samples of MH. The characterization of raw and torrefied-MH in terms of proximate ‒ ultimate analysis and compositions of hemicellulose, cellulose, and lignin, was carried out. Further, exergy analysis of MH before and after torrefaction ensured the improvement of the heating value of MH. Torrefaction increased the heating value and carbon content of torrefied-MH by 21.5 % and 25.67%, respectively. For the kinetic study, non-isothermal TGA ‒ DTG thermograms were recorded for raw- and torrefied samples of MH at four different heating rates ranging from 5 to 30°C/min. Kinetic predictions were then made using multiple linear regression method (MLRM) as well as regular integral isoconversional methods. MLRM shows that reaction order, as well as activation energy and pre-exponential factor, varies during MH pyrolysis. Further, regular integral isoconversional methods predicted that for 5 ‒ 70% of fractional conversion, the average activation energy ranged from 210.96 to 212.07 kJ/mol for raw-MH and 99.08 to 104.38 kJ/mol for torrefied-MH.