NOVELTY - Biomass torrefaction system (10) comprises: inlet (22) to receive biomass particles; reactor drum (12) configured to rotate about axis of rotation; heat source (30) to heat gas contained in system to temperature sufficient to torrefy biomass particles during operation; fan device coupled to system to create, when system is in operation, heated gas stream (34) through reactor drum to intermittently transport biomass particles along longitudinal length of reactor drum as biomass particles are lifted by flights and showered through heated gas stream as reactor drum rotates; and duct system.    USE - Used as biomass torrefaction system.    ADVANTAGE - The biomass torrefaction system provides a highly efficient medium for transferring heat to the biomass particles directly, thus processing large volumes of biomass particles with reduced energy demands.    DETAILED DESCRIPTION - Biomass torrefaction system (10) comprises: an inlet (22) to receive biomass particles; a reactor drum (12) configured to rotate about an axis of rotation, where the reactor drum has many flights positioned in it; a heat source (30) 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 (34) through the reactor drum to intermittently transport the biomass particles along a 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 a duct system 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. An INDEPENDENT CLAIM is also included for biomass torrefaction, comprising: rotating the reactor drum about an axis of rotation; generating a heated gas stream through the reactor drum to intermittently transport biomass particles along a longitudinal length of the reactor drum and simultaneously torrefy the biomass particles as the biomass particles are lifted by the flights and showered through the heated gas stream as the reactor drum rotates; and recirculating a portion of gas exiting the reactor drum back to an inlet of the reactor drum for torrefying biomass particles within the reactor drum.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of the biomass torrefaction system.    Biomass torrefaction system (10)    Reactor drum (12)    Inlet (22)    Heat source (30)    Gas stream (34)