Intertwining action of additional fiber in preparation of waste sawdust for biofuel pellets

Exploitation of biomass pellets (BPs) as biofuels greatly addresses the global energy and environmental crisis. The quality of the BPs highly depends on its mechanical bonds. Pre-heating and high pressure were usually introduced to reinforce the bonds in BPs, but they consumed more energy and presented the complexity of producing process. Herein, we found that linen fibers incorporated into the wood sawdust particles has a positive effect on reinforcing the mechanical bonds in BPs prepared under modest conditions. The reinforced role of the additional linen fibers in BPs is investigated by evaluating their product qualities. Results showed that the qualities of BPs like relaxed density (ρ), abrasive resistance (AR) and impact resistance index (IRI) of BPs were significantly enhanced to 1.08 kg dm−3, 0.65% and 200 after adding fibers in length ranged from 2 mm to 10 mm. Light microcopy images of the BPs cross-sections showed that the reinforced bonding mechanism of additional fibers was probably attributed to the intertwining action. Thus, a new mold of reinforcement in the BPs is presented.