Pyrolysis of sorghum bagasse biomass into bio-char and bio-oil products

Abstract

The transformation of renewable biomass into valuable products as alternatives to fossil fuels is essential for sustainable energy in sustainable society. This work systematically investigates the pyrolysis of sorghum bagasse biomass into bio-char and bio-oil products and studies the effect of temperature (623–823 K) on the conversion of sorghum bagasse and products yields. The physicochemical properties of bio-char were thoroughly studied using powder X-ray diffraction, elemental analysis (CHNSO), scanning electronic microscope, calorific value (CV), and Fourier transform infrared (FTIR) spectroscopy techniques. Also, gas chromatography–mass spectrometry (GC–MS), CV, and FTIR were used to understand the properties of bio-oil. The results obtained indicate that an increase in the pyrolysis temperature from 623 to 823 K leads to a decrease in the bio-char yield from 42.55 to 30.38%. On the other hand, the maximum bio-oil yield of 15.94% was obtained at 723 K. The bio-char obtained at 673 and 773 K was found by FTIR analysis to be composed of a highly ordered aromatic carbon structure. The calorific value of bio-oil, which contains a greater amount of acidic compounds, was found to be 6740 kcal/kg. The GC–MS analyses revealed the presence of octadecenoic acid, p-cresol, 2,6-dimethoxy phenol, 4-ethyl 2-methoxy phenol, phenol, o-guaiacol, and octadecanoic acid in the bio-oil obtained from the pyrolysis of sorghum bagasse biomass. The present study provides useful information for understanding the quality of bio-oil and bio-char obtained from high biomass sorghum bagasse.