Quality of pellets from torrefied biomass and pellets torrefied at different temperatures

Torrefaction is a mild thermal treatment in an inert atmosphere, which is known to increase the energy density of biomass on a mass basis (MJ kg-1). By combining the torrefaction process and pelletization the specific energy density on volume basis is further increased would thus allow for more cost effective volume limited transport. There are two ways of combining torrefaction and pelletization: pelletize torrefied biomass and torrefy regular pellets. The former is the one used for producing commercial torrefied pellets, while the latter one could be relevant for power plant which has facility to do torrefaction before co-firing. In this study, both ways were utilized to produce torrefied pellets. The quality of these pellets have been characterized for higher heating value (HHV), energy consumption during grinding, mechanical durability and equilibrium moisture content (EMC) under different humidity.