Friction properties of pellets made of wood and straw

Abstract

The aim of the work was to obtain knowledge of the friction properties of materials subjected to pressure agglomeration (wood pellets and straw pellets). The frictional properties of the tested materials were evaluated by: the angle of internal friction and the effective internal friction angle of pellets, uniaxial shear strength, material flowability coefficient and the cohesion value of the material. Wooden pellet has a higher strength on uniaxial compression average of 36.2 kPa than the pellet made of straw, approximately of 31.3 kPa. Based on the flowability index, it was found that straw and wood pellets are easily flowing (4 < ffc < 10). The values of the internal friction angles were higher for biomass made of wood than from straw, and were 50.02ºand 35.17º, respectively. Pellets made of straw were more cohesive materials (approximately 8000 Pa) than the pellets made of wood (approximately 6600 Pa).