Thermal behaviour, kinetics and fast pyrolysis of Cynodon dactylon grass using Py-GC/MS and Py-FTIR analyser

Abstract

Cynodon dactylon (DG) is a biological resource available in abundance across the world; and has the capability to yield sustainable renewable fuels and fine chemicals. The present study explored the bioenergy potential of DG biomass by evaluating its physicochemical properties, pyrolysis characteristics, and kinetic behaviouer with thermodynamic analysis (TD) for the first time. The physicochemical outcome established its bioenergy potential towards sustainable energy production. The thermal decomposition study of DG biomass was carried out in a thermogravimetric analyser (TGA) at dynamic heating rates (10, 30 and 50 °C min−1), under nitrogen atmosphere while Py-GC–MS was executed to understand the pyrolysis behaviour. The thermal decomposition profile of the DG biomass established multistage degradation, which is linked to the diverse components in its structure. The average apparent kinetic energy was found to be 208.89, 220.43, 211.90, 213.66, 214.28 and 192.30 kJ mol−1 for Kissinger-Akahira-Sunose (KAS), Ozawa-Flynn-Wall (OFW), Friedman (FM), Starink (ST), Distributed Activation Energy Model (DEAM), and Vyazovkin (VZ). Py-GC–MS results revealed that formation of phenolics, aromatic hydrocarbons and ketones in the temperature range 450–650 °C were increased while formation of cyclopentanones, acids, esters and other oxygenated compounds were reduced. Finally, Py-FTIR study confirmed that the majority of functional groups generated in the range of 4 −15 s.