The combined production of the most abundant agricultural residues in Spain (viz. cereal straw, sunflower
stalks, vine shoots, cotton stalks, olive, orange and peach tree prunings, and horticultural and related residues) amounts to
over 50 million tons per year, more than 20% of which is generated by Andalusia alone.
Agricultural residues must be disposed of for various reasons including the facts that they promote contamination and pest
growth, occupy large expanses of land and hinder agricultural work. Ideally, the disposal method used should allow their
major components (cellulose, hemicellulose and lignin) or their chemical potential energy to be exploited.
Agricultural residues can be valorized by converting their components jointly (combustion, pyrolysis, gasification, liquefaction)
or separately (fractionation).
The most useful method for exploiting such components separately involves isolating cellulose fibres for papermaking
purposes. In recent times, this valorization method has led to the development of the biorefining concept. Biorefining involves
the fractionation or separation of the different lignocellulosic components of agricultural residues with a view to
their integral exploitation rather than the mere use of cellulose fibre to obtain paper products.
Biorefining replaces the classical pulping methods based on Kraft, sulphite and soda reagents with a hydrothermal treatment
followed by organosolv pulping. The hydrothermal treatment provides a liquid phase containing hemicellulose decomposition
products [both oligomers and monomers (glucose, xylose, arabinose)] and a solid phase rich in cellulose and
lignin. By contrast, the organosolv process gives a solid fraction (pulp) and a residual liquid fraction containing lignin and
other useful substances for various purposes.
Hydrothermal treatment of antibiotic mycelial dreg: More understanding from fuel characteristics
