Mechanical characteristics of pine biomass of different sizes and shapes

In the present study, the mechanical properties of granular biomass of pine origin (sawdust, shavings, long shavings and pellets) were determined. The bulk and tapped densities were determined in a cylindrical chamber. The compacted density was measured, and the influence of the moisture content on this quantity was examined in a vane tester. The flowability and strength properties were determined using a direct shear tester (Jenike box) 210 mm in diameter and standard Schulze ring shear tester. The tests in the Jenike tester complied with the Eurocode 1 procedure for normal pressure (σn) of 15 and 30 kPa and speed of shearing of 0.17 mm s−1. Ring shear testing was conducted using a Schulze annular shear cell of 195 mm outer diameter. Tests were performed for 10 and 20 kPa pre-shear σn. A prototype vane tester was constructed for determining the torque, shear strength, and relaxation of a consolidated sample of granular biomass. σn was exerted by a pneumatic system with a rubber air spring and yoke. The torque and density were measured for moisture content in the range of 10–50% and for σn in the range of 5–30 kPa. The torque was observed to be affected by σn and the moisture content, whereas no relationship between the torque and the rotational speed was observed.