Patent ID: 8246788

Claim:
A biomass torrefaction system, comprising: an inlet to receive biomass particles; a reactor drum configured to rotate about an axis of rotation, the reactor drum having a plurality of flights positioned therein at a plurality of locations along a longitudinal length of the reactor drum; a heat source upstream of the reactor drum to heat gas contained in the system to a temperature sufficient to torrefy the biomass particles during operation; a fan device coupled to the system to create, when the system is in operation, a heated gas stream through the reactor drum sufficient to intermittently transport the biomass particles along the longitudinal length of the reactor drum as the biomass particles are lifted by the flights and showered through the heated gas stream as the reactor drum rotates; and gas ducts coupled to at least the reactor drum, heat source and fan device to recirculate at least a portion of gas exiting the reactor drum back to the heat source to reheat the gas for reintroduction into the reactor drum.