Background

While torrefied wood chips can easily be formed into high-energy, high-density pellets, doing so burns off most of the natural binders, resulting in pellets with poor water repellency. Furthermore, such pellets can turn into a black “mud” upon exposure to water. Another problem with torrefied wood pellets is low durability. The pellets can create dust that not only results in product loss, but high concentration of dust fines that clump together. The consequent clinkering reduces boiler efficiency, poses inhalation hazards and increases the potential for dust explosions. This new method creates water-resistant and durable high-energy-density torrefied wood pellets or briquettes with biomass-based binders. By adding binders that melt and flow under the extruder conditions, this process coats and protects