NOVELTY - A method of torrefaction of lignocellulosic biomass involves continuously feeding the biomass to upper inlet (14) of the torrefaction reactor vessel (10) such that the biomass material is deposited on upper tray of trays stacked vertically within the reactor; as the biomass moves across upper surface of each of the trays, heating and drying the biomass material with gas injected into the vessel; cascading the biomass down through the trays; discharging torrefied biomass from lower outlet of the vessel; and circulating gas extracted from lower elevation of the vessel to upper region.    USE - For torrefaction of lignocellulosic biomass (claimed) such as wood chips, wood pulp and other comminuted cellulosic material.    ADVANTAGE - The method reduces volume of hot gas needed in the pressurized reactor. The volume, size and cost of the vessel are reduced as compared to a vessel operating at atmospheric pressure. A pressurized vessel in which a hot gas is injected provides effective and economical heat transfer from the gas to the biomass in the vessel.    DETAILED DESCRIPTION - A method of torrefaction of lignocellulosic biomass using torrefaction reactor vessel (10) having stacked trays involves continuously feeding the biomass to upper inlet (14) of the torrefaction reactor vessel such that the biomass material is deposited on upper tray of trays stacked vertically within the reactor; as the biomass moves across upper surface of each of the trays, heating and drying the biomass material with gas injected into the vessel, where the gas is non-oxidizing of the biomass, is under pressure of at least 20 bar gauge, and at 200 degrees C; cascading the biomass down through the trays by passing the biomass through opening in each of the trays to deposit the biomass on lower tray; discharging torrefied biomass from lower outlet of the torrefaction reactor vessel; and circulating gas extracted from lower elevation of the reactor vessel to upper region of the reactor vessel. An INDEPENDENT CLAIM is included for torrefaction pressurized reactor vessel assembly comprising stack of trays housed within the vessel; source of pressurized, reduced oxygen gas coupled to the vessel to allow the gas to flow into at least an upper region of the vessel, where the gas is at a pressure of at least 20 bar gauge and at a temperature of at least 200 degrees C; an upper inlet to the vessel through which biomass enters the pressurized reactor vessel, where chute aligned with the upper inlet directs the biomass from the inlet to an upper tray of the stack of trays; a scraper device associated with an upper surface on each of the trays, where at least one of the scraper device and tray rotates within the vessel; lower outlet in the vessel through which torrefied biomass is discharged from the torrefaction reactor vessel, and a gas circulation system through which gas extracted from a lower elevation in the vessel flow to an upper elevation of the reactor vessel.    DESCRIPTION OF DRAWING(S) - The figure shows pressurized treatment vessel receiving biomass from feed system.    Heat exchanger (9)    Vessel (10)    Separate dryer (11)    Upper inlet (14)    Upper drying zone (15)    Conduit (23)