High-Moisture Pelleting Process – Idaho National Laboratory
Idaho National Laboratory has developed a high-moisture pelleting process that decreases the drying cost and manages the feedstock moisture more efficiently. Through this process, the biomass is pelleted at moisture contents greater than 25 percent. The pellets are partially dried during production by the frictional heat developed in the pellet die during compression and extrusion. Additionally, a short preheating step replaces the conventional, energy-intensive steam conditioning. This step helps reduce the feedstock moisture content as well as activate biomass components, like lignin. Techno-economic analysis indicated the process reduces energy and production costs by about 40 to 50 percent compared to a conventional pelleting method. Currently, scale-up of the high moisture pelleting process from lab to pilot and commercial scale is in progress.