Effect of temperature on oil quality obtained through pyrolysis of sugarcane bagasse

Abstract

The effect of temperature (300–650 °C) on the bio-oil quality and yields during pyrolysis of sugarcane bagasse was investigated. Results showed that temperature had a profound influence on the pyrolysis products’ yields and bio-oil quality. Elemental analyses of bio-char and bio-oil showed that the carbon content in bio-char increased from 15.25% to 19.31% with increase in temperature from 300 °C to 500 °C and then decreased to 19.18% at 600 °C. Bio-oil and bio-char yields were seen to increase and decrease with an increase in pyrolysis temperature, respectively. Highest bio-oil yield (56.6% wt) was achieved at 500 °C while maximum amounts of bio-char (53.5% wt) and gas (32.9% wt) were obtained at 300 °C followed by at 400 °C. Highest HHV for bio-char (11.78 MJ/kg) was recorded at 500 °C, which decreased with further increase in temperature to 600 °C. Conversely, highest HHV for bio-oil (25.91 MJ/kg) was obtained at 300 °C. The obtained bio-oils were enriched in lignin derivatives and sugars oligomers and their concentration increased with increase in temperatures from 450 to 550 °C. FTIR spectra revealed the presence of aromatics, ethers, alkanes, alkenes and other alcohols in bio-char. Whilst alcohols, alkenes, ethers and other alcohols were noticed in the bio-oil. The complete absence of aromatics in bio-oil facilitates long-term stability of the bio-oil. These results suggest that good yields and high-quality bio-oil from sugarcane bagasse could be obtained at pyrolysis temperature of 550 °C. However, for an efficient pyrolysis process with relatively high bio-oil yields, pyrolysis reactor should be operated at 450 °C.