NOVELTY - System comprises an arrangement including a rotary tube (10) having a gradient in the flow direction of the treated biomass. The lumpy biomass (21) supplied at the upper end of the rotary tube migrates to the lower end of the rotary tube under the rotation of the rotary tube. The biomass is heated in a first zone (11) through indirect heat exchange, where freed gases and vapors are dissipated. The biomass is heated in a second zone (12) through indirect heat exchange to achieve a biomass-target temperature.    USE - The system is useful for continuous thermal treatment of biomass for manufacturing millable solid-fuels having high calorific value.    ADVANTAGE - The system includes store installs installed within the heat transfer surfaces for increasing the turbulence, reduces accelerated accumulation of the carbon present in the fuel through heat supply, and produces small amount of hydrogen and water from the fission products.    DETAILED DESCRIPTION - System for continuous thermal treatment of biomass for manufacturing millable solid-fuels having a high calorific value, comprises an arrangement including a rotary tube (10) having a gradient in the flow direction of the treated biomass. The lumpy biomass (21) supplied at the upper end of the rotary tube migrates to the lower end of the rotary tube under the rotation of the rotary tube. The biomass is heated in a first zone (11) through indirect heat exchange at 250-600 degrees C, where freed gases and vapors are dissipated. The biomass is heated in a second zone (12) through indirect heat exchange to achieve a biomass-target temperature (290 degrees C). The biomass is cooled in a third zone (13) by indirect heat exchange for terminating the onset of pyrolysis. The biomass is removed at the lower end of the rotary tube as a carbonated, biogenic material to be dried.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic representation of the apparatus having heat exchanger surfaces operating in a countercurrent principle as a process diagram, the drawing includes non English language text.    Rotary tube (10)    First zone (11)    Second zone (12)    Third zone (13)    Biomass (21)