Charcoal productivity and quality parameters for reliable classification of Eucalyptus clones from Brazilian energy forests

Abstract

Charcoal productivity in brick kilns is controlled by factors such as, the pyrolysis process and kind of raw material, which impose a challenge for the selection of the best clones. This study investigates the tree growth characteristics as a parameter for the improvement of selection and classification of Eucalyptus clones, with the quality and availability required by the steel industry, in addition to the properties of wood and charcoal. Parameters as the diameter at breast height (DBH), total height, and wood basic density (WBD) of fourteen clones were measured. Wood specimens were converted to charcoal in laboratory conditions and the carbonization yields, charcoal properties, and the volume of wood required to produce 1 t of charcoal (specific consumption) were evaluated. Eucalyptus clones with DBH ≥15.1 cm, WBD ≥560 kg/m3, and gravimetric yield ≥35% provided low specific consumption (<5.1 m³/t), increased brick kilns productivity, and resulted in denser charcoals (380 kg/m3). Clones with WBD ≤500 kg/m3 are not recommended for steel charcoal production. The E. urophylla x E. camaldulensis hybrid (clone 1004), E. urophylla (clone 1009), and E. grandis hybrid (clone 1039) highlighted due to the productivity, bioreducer quality, and specific consumption (<5.2 m³/t).