Torrefaction is a new twist on an old process that roasts wood chips (or other biomass) in a low oxygen environment. This boils off volatiles and low energy density elements such as hemicellulose to leave a visually darker wood chip that has a higher energy density than regular wood and a natural resistance to moisture. Applications for this product are still developing, but include High Energy Pellets, Gasification, Biofuel Feedstock and Advanced Materials. The TSI process is a patented system based on a rotary drum. The heat energy is produced by indirectly heating the gas that circulates through the system. The process produces a form of Syngas that is ducted back to the burner and can make the process auto-thermal.