Biomass is attracting increasing interest from researchers as a renewable, sustainable and clean energy source. It can be converted to bio-oil by thermochemical methods, such as gasification, liquefaction, and pyrolysis, and used to produce fuels, chemicals, and biomaterials.
In Journal of Renewable and Sustainable Energies, researchers from the Heilongjiang Academy of Agricultural Machinery Sciences in China share their work on the physicochemical properties and the antioxidant activity of wood vinegar and the tar fraction in bio-oil produced from the pyrolysis of hazelnut shells at 400 Â° C to 1000 Â° C.
Wood vinegar is often used in agricultural fields as an insect repellant, fertilizer, and plant growth promoter or inhibitor, and can be applied as a deodorant, wood preservative, and feed additive.
âAfter these results, wood vinegar and tar obtained from residual hazelnut shells could be considered a potential source of renewable energy based on their own characteristics,â said author Liu Xifeng.
The researchers found that the wood vinegar and tar that remained after burning the shells contained the most phenolic substances, which laid the groundwork for further research into antioxidant properties.
The experiments were carried out in a tube furnace pyrolysis reactor, and samples of hazelnut shells weighing 20 grams were previously placed in the waiting area of ââa quartz tube. When the target temperature was reached and stable, the raw materials were pushed to the reaction region and heated for 20 minutes.
Biochar was determined as the ratio of pyrolytic carbon to the weight of biomass, and the bio-oil yield was calculated by the increased weight of the condenser.
To sufficiently separate two bio-oil fractions, the liquid product was centrifuged at 3200 rpm for eight minutes, and the aqueous fraction was called wood vinegar. The separated tar fraction remained stationary for 24 hours without the appearance of the aqueous phase.
Wood vinegar and tar were respectively stored in a sealed tube and kept in a refrigerator at 4 Â° C for experimental analysis, and the gas yield was calculated considering their combined volume.
The researchers found that the pyrolysis temperature had a significant effect on the yield and properties of wood vinegar and the tar fraction in bio-oil obtained from hazelnut hulls. Wood vinegar was the dominant liquid fraction with a maximum yield of 31.23 percent by weight obtained at 700 Â° C, attributable to the high concentration of water.
This research lays the groundwork for new applications of bio-oil from the pyrolysis of hazelnut shells, and its application in antioxidant activity has been extended.
– This press release was provided by the American Institute of Physics