Hazelnuts are delicious, but can their husks be used to create renewable energy? According to Chinese researchers, the hulls of the nuts could be a good source of biomass to create biofuels.
The new research focuses on how hazelnut shells respond to the pyrolysis process – by superheating them to temperatures between 400 and 1,000 ° C and analyzing what is left.
The word pyrolysis comes from the Greek terms pyro for “fire” and lysis which means “to separate”.
Exploring how different sources of biomass react to this type of process could lead to new, highly efficient bio-oils that could be used in manufacturing processes such as the production of (cleaner) fuels and / or chemicals.
In the study, researchers at the Heilongjiang Academy of Agricultural Machinery Sciences in China used pyrolysis to obtain products called “wood vinegar” and “tar fraction” from the hazelnut shells.
Wood vinegar is already often used in agriculture as an insect repellant, fertilizer, plant growth activator or inhibitor, or can be used as a deodorant, wood preservative and as an additive for animal feed.
The tar fraction could replace heavy oil for industrial boilers, or it could be used as a liquid fuel for industrial raw materials, the researchers suggested.
“After 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,” said study author Liu Xifeng. .
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 peak yield of 31.2% by weight obtained at 700 ° C, which the researchers said was due to the high water concentration.
Despite the authors’ claim that “biomass is attracting increasing interest from researchers as a renewable, sustainable and clean energy source”, concerns remain about its overall impact on the environment, compared to the use of renewable energy sources such as wind and solar. Power.
Burning biomass fuels in industrial quantities can release large amounts of CO2, which, if not captured and stored efficiently, will enter the atmosphere, exacerbating the climate crisis.
The research team said their work on hazelnut shells “lays the groundwork for other applications of bio-oil from the pyrolysis of hazelnut shell waste.”
The research is published in the Journal of Renewable and Sustainable Energy.