NOVELTY - A reaction mixture comprising biomass is heated by contacting with steam to obtain a reaction mixture comprising activated biomass. The steam moves counter-currently with respect to the reaction mixture. The activated biomass is polymerized to obtain a reaction mixture comprising coal-like material.    USE - Hydrothermal preparation of coal-like material from biomass. Uses include but are not limited to wood flour, wood waste, scrap wood, sawdust, chips, rice straw, chaff, bagasse and waste paper.    ADVANTAGE - The method enables economical hydrothermal preparation of coal-like material, with high yield and reduced energy consumption. The clogging of column during hydrothermal preparation of coal-like material is suppressed.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for column (100), which has at least one horizontally-oriented mass transfer tray with perforations, a perforation-providing unit which communicates between space above and space below the mass transfer tray, at least one vertically-oriented rotor shaft (5) which pass through a rotor shaft opening in the mass transfer tray, at least one upper rotor element (10a) mounted on the rotor shaft and is disposed above the mass transfer tray, the upper rotor element is arranged to transfer the reaction mixture through the perforations to the space below the mass transfer tray, and a housing comprising an upper inlet and upper outlet at the upper end, and comprising a lower inlet and lower outlet at lower end. The upper inlet permits to-be-introduced more-viscous fluid into the column, and the lower outlet permits fluid out of the column. The lower inlet permits to-be-introduced less-viscous fluid into the column, and the upper outlet permits fluid out of the column. The mass transfer tray is disposed within the housing.    DESCRIPTION OF DRAWING(S) - The drawing shows the flow diagram of hydrothermal preparation of the coal-like material.    Rotor shaft (5)    Rotor elements (10a,10b)    Column (100)    Swamp section (103)    Stirring unit (110)