Parameters to determine mechanical strength of charcoal in a hydraulic press

Abstract

The friability, an important quality parameter, is the ability of charcoal to generate fines when it is moved. However, there is no standard for determining the compressive strength of charcoal beds. Thus, the objective of this work was to evaluate some test parameters for determining the generation of charcoal fines in a manual hydraulic press. Charcoal was produced with eucalyptus logs 7 years old, diameters of 10 to 12 cm, and length of 1 m in a circular surface kiln, with a maximum carbonization temperature of 400 ºC and a total time of 58 hours. For methodology evaluation, charcoal mechanical tests were performed in a manual hydraulic press, using as test variables four charcoal granulometric ranges (12.7 to 19.5; 19.5 to 25.4; 25.4 to 31.7 and 31.7 to 50.8 mm) and five compressive loads (1; 1.5; 2; 3 and 5 t). The reference was the drum test. The method of evaluating the mechanical strength using a manual hydraulic press is suitable for determining the strength of a charcoal bed, because it represents the efforts that charcoal supports in industrial systems. The test parameters recommended for determining the mechanical strength of charcoal, using a manual hydraulic press, are: compressive load of one ton; charcoal with granulometry of 19.5 to 50.8 mm; average velocity of force application of 1 mm s^-1; and, charcoal time under pressure equal to 1 min.