Biomass Screening for the Production of Furfural via Thermal Decomposition

Packed-bed pyrolysis (heating temperature 800 K) is studied of beech and fir wood, several agro-industrial residues (corn cobs and stalks, olive husks, wheat straw, hazelnut and almond shells, orange peels, grape residues, artichoke stems, brewer's spent grain, and pruning cuts from cherry, olive, vine, and poplar trees) and cellulose, aimed at determining the potentially most promising feedstock for the production of furfural. Parameters associated with conversion dynamics are mainly affected by the packed-bed density (0.1-1.1 g/cm3) whereas products mainly depend upon the feedstock chemical composition. In particular, the yields of condensable organic products increase with the holocellulose content (10-85%) up to 25-40% (dry sample mass basis). The higher yields of furfural (dry organics mass basis), in the range 2-0.8%, are obtained from feedstocks with significant contents of cellulose/ pentoses (corn cobs, almond shells, hardwoods such as beech, cherry, olive, and poplar woods, orange peels, corn stalks, and hazelnut shells), while interesting quantities (approximately 1-0.4%) of 2(5H)-furanone are observed in all cases. As expected, the highest yields of hydroxyacetaldehyde and levoglucosan (about 8 and 3%) are produced from fir wood. On the other hand, some agro-industrial residues (hazelnut and almond shells and olive husks), apart from acetic acid, also produce high yields of phenolic compounds.