An investigation into the pyrolysis and oxidation of bio-oil from sugarcane bagasse: Kinetics and evolved gases using TGA-FTIR

Bio-oil produced from the pyrolysis of sugarcane bagasse has the potential to be used as a sustainable and renewable energy source. In the present study, a non-isothermal thermo-gravimetric analysis (TGA) of the pyrolysis (in N₂ atmosphere) and combustion (in the air) of bio-oil from sugarcane bagasse was investigated at three heating rates: 5, 10, and 20 °C/min. The sample was heated from room temperature up to 900 °C and the evolved gases in the TG furnace were carried to a Fourier transform infrared (FTIR) cell where the composition of the gases and the functional groups present there were analyzed. A global kinetic analysis was performed to obtain the Arrhenius kinetic parameters for the pyrolysis and oxidation of the bio-oil using the distributed activation energy model. Three distinct stages, namely; low-temperature oxidation (LTO), fuel decomposition (FD), and high-temperature oxidation (HTO) were observed during the oxidation of bio-oil. The initial devolatilization of the oxygenated compounds observed during pyrolysis was similar to the LTO stage observed during combustion. The intensity of the CO₂ FTIR peaks seen during the bio-oil combustion was 10 times the intensity of the CO₂ peaks attained during pyrolysis. The TGA-FTIR analysis of the sugarcane bagasse bio-oil sheds new light on its thermal degradation/oxidation characteristics.