NOVELTY - The method comprises directly contacting a material flow to a reactor (1) with a low-oxygen inert hot gas flow. The hot gas stream (50%) is formed by a thermal treatment process (7) of gas. An exhaust gas of the reactor is fed to the thermal treatment process as a gaseous fuel. The treated carbonaceous material flow as a solid fuel is present in the reactor. The hot gas stream is used for drying and/or torrefaction of the material flow in the reactor. The drying gas is used for water production. During the torrefaction, torrefikate is hot ground and/or briquette and is cooled using a cooler.    USE - The method is useful for increasing a calorific value of a carbonaceous material flow such as a material flow from renewable raw material.    ADVANTAGE - The method is capable of increasing the calorific value of the carbonaceous material flow with less energy consumption.    DETAILED DESCRIPTION - The method comprises directly contacting a material flow to a reactor (1) with a low-oxygen inert hot gas flow. The hot gas stream (50%) is formed by a thermal treatment process (7) of gas. An exhaust gas of the reactor is fed to the thermal treatment process as a gaseous fuel. The treated carbonaceous material flow as a solid fuel is present in the reactor. The hot gas stream is used for drying and/or torrefaction of the material flow in the reactor. The drying gas is used for water production. During the torrefaction, torrefikate is hot ground and/or briquette and is cooled using a cooler. A biochar torrefaction is generated and is used as a reducing agent in a pyrometallurgical process. The thermal treatment process is performed by a cement clinker and/or lime burning method, a pyrometallurgical process and/or a method for generation and/or oil production. The hot gas flow is used for preheating of cement raw meal and/or lime and/or ore, and is introduced with an oxygen content of less than 8% at a temperature of less than 450 degrees C into the reactor. A part of the reactor derived from the exhaust gas is used for the recovery of an organic acid by the exhaust gas, and is fed to a condenser and/or a rectifying column. An INDEPENDENT CLAIM is included for a system for the thermal processing of cement raw material, limestone or ore.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a method for increasing a calorific value of a carbonaceous material flow.    Reactor (1)    Media (3)    Thermal treatment process (7)    Cooler exhaust (10)    Hopper. (12)