Physical and thermal characterization of ground bark and ground wood particles

The present work reports the physical, size and shape, flowability, drying and devolatilization properties of ground wood and ground bark particles. Mechanical sieving and image processing identify the size and shape of ground particles, respectively. Ground particles are dried at initial moisture contents of 0.30, 0.50, 0.70 and 0.90 (dry mass basis) and drying temperatures of 70, 100, 130 and 160 °C. Devolatilization rate of particles is measured using a thermogravimetric analyzer. Microscopic investigations show that wood particles are longer and thinner than bark particles. More spherical shape facilitates the flowability of the bark particles. Wood particles are cohesive and have poorer flowability properties than bark particles. Bark particles have a lower internal void fraction than wood particles. Denser structure of bark particles diminishes the drying and devolatilization rate and prolongs the heat and mass transfer process compared to the wood particles.