In-depth investigation on thermochemical characteristics of palm oil biomasses as potential biofuel sources

• The thermochemical properties of the different palm oil biomasses were investigated.
• Palm oil biomasses are advantageous to pyrolysis processes for clean energy generation.
• Empty fruit bunches (EFB) pyrolysis indicated the highest yield of the bio-oil.
• Palm kernel shell (PKS) bio-oil showed high quantity of phenolic compounds.

The accurate determination of the biomass thermal properties is particularly important while studying biomass pyrolysis processes. The aim of this study is to investigate the different palm oil biomass samples (palm kernel shell (PKS), empty fruit bunches (EFB) and palm mesocarp fiber (PMF)) thermochemical behavior during pyrolysis. Thermogravimetric analysis coupled with spectroscopy (mass spectroscopy (TGA-MS) and Fourier transform infrared spectroscopy (TGA-FTIR)) and also differential scanning calorimetry (DSC) were employed to investigate the biomass thermal degradation. TGA and DSC results were obtained at temperature ranging from 25 °C to 850 °C and 500 °C, respectively, using pure nitrogen as inert gas and at the heating rate of 15 °C/min. TGA curves showed different stages for the biomasses thermochemical behavior associated with dehydration (stage 1), slow depolymerization (stage 2) and pyrolytic degradation (stage 3), while DSC indicated the caloric requirement in these stages. The main permanent evolved gases comprising H2, CO2, CO were detected online during analysis. The major permanent gases produced at the temperature range of 250–750 °C were attributed to the biomasses pyrolysis, oxygenated functional groups cleavage and probably some secondary reactions. Furthermore, the bio-oils produced from the different biomasses pyrolysis, in a fixed-bed reactor, were analyzed by GC–MS and FTIR. The pyrolysis kinetics of different palm oil biomasses were investigated using the Coats-Redfern model.