Effect of Densification Conditions on Physical Properties of Pellets Made From Sawmill Residues

Abstract

Sawmill residues produced in wood processing of Pilon (Hyeronimaalchorneoides) and Eucalyptus (Eucalyptus spp) species, were used to fabricate pellets with experimental design equipment. Different manufacturing conditions as the diameter (8 mm − 10 mm), compression force (300 kgf − 500 kgf) and temperature applied during densification (90 °C − 105 °C), were employed in order to evaluate its effect on unit density, bulk density and durability of pellets produced. Values between 0.856 kg/dm3 and 1.093 kg/dm3 for unit density, 480.0 kg/m3 and 603.0 kg/m3 for bulk density were determined. For durability, values between 96.1% and 97.5% were determined. Significant increase in values determined for unit and bulk density were founded, with diameter reduction and compressive force increasing. Durability was the least sensitive property to the effect of studied densification conditions, whose variation was not significant between similar densification treatments. The effect of temperature generally had less impact on physical properties evaluated. The comparison of results against European standards for wood pellet quality, showed that fabricated pellets fulfills values defined for physical properties in different categories.