An assembly for processing green biomass material for pelletizing into a fuel pellet includes a heating assembly, a drying assembly and a cooling assembly. The heating assembly heats a thermal fluid to a temperature within the range of 200° F. to 550° F. The drying assembly includes a rotating dryer drum that has a plurality of thermal fluid tubes therein. Material that is dried in the dryer drum is conveyed to a rotating cooling drum that has a cooling tube extending along the interior thereof. A nozzle is mounted on the end of the cooling tube to discharge cooling fluid on the material therein, and a plurality of flights are mounted on the interior of the cooling drum and arranged to direct material from the inlet to the discharge outlet as the cooling drum is rotated.