Study on the effects of raw materials composition and pelletization conditions on the quality and properties of pellets obtained from different woody and non woody biomasses

Pellets obtained from 2 mm milled materials showed higher mechanical durability values. Pellets obtained from woody materials, which exhibited lower extractives and higher lignin contents, evidenced also a higher physical quality. Power demand and temperature of the die were also higher for woody materials, suggesting a higher friction inside the die channels. SEM images showed a closer agglomeration of the particles when materials were milled at 2 mm. Woody particles had a more evident deformation when pelletized while herbaceous materials preserved their shape. Different bonding interactions could be observed in pellets from different materials.