Effect of waste wrapping paper fiber as a “solid bridge” on physical characteristics of biomass pellets made from wood sawdust

Densified biomass pellets using waste wood sawdust (S) as main materials and wrapping paper fiber (P) as “solid bridge”, named as P/S-BPs, was prepared by a hydraulic press powder pelletizer under room temperature and pressure lower than10 MPa. The effects of the addition of P to S and the compressed pressure on the density, resiliency (R), abrasion resistance (AR), impact resistance index (IRI)) and the combustion behavior of the P/S-BPs were investigated. The results showed that the addition of P to S greatly reduced the negative effects of resiliencies on the densities and mechanical properties of P/S-BPs during storage. For example, P/S-BPs compressed at 6 MPa in a P/S mass ratio of 1–3 showed the smooth surface and low resiliency of 10% with a high relaxed density of 1.08 kg m−3. This is due to the strengthened interlocking bonds through fabricating “solid bridge” and increasing attracting force by adding P to resist the disruptive force created by elastic recovery even under low pressure. Combustion results showed that the addition of P decreased the soot index (SI) due to the lower devolatilization rate and burnout rate, and increased the HHV per unit volume because of its high relaxed density. Thus, compression of waste P and S in a P/S mass ratio of 1–3 at room temperature under 6 MPa is a cost-effective process to produce densified sustainable bio-fuel from waste S and P as well as dispose them.

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► Sawdust was densified into sustainable and CO2-neutral biomass pellets fuel.
► Sawdust is combined using waste wrapping paper fiber (P) as a “solid bridge”.
► Pellets are prepared at modest condition due to the fabrication of “solid bridge”.
► The modest processing condition is low energy consumption and cost-effective.
► The addition of P increased the HHV per unit volume of pellets.