TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The control unit is used for operating the circulation pump until temperature difference between the first and a third heating chamber (3) became less than the set value before operating a third heating chamber, where circulation pump is connected first and third heating chambers, and then operating the circulation pump until temperature difference between the second and third heating chamber became less than the set value, where circulation pump is connected to the second and third heating chambers. The device further comprises a heating unit for applying heat inside each of the heating chamber, a water supply unit for supplying water inside each of the heating chamber, a functional chemicals supply unit for supplying zinc chloride inside each of the heating chamber, an oxygen supply unit for supplying oxygen inside each of the heating chamber, and at least one vacuum pump unit for maintaining internal vacuum of the active heating chamber, or a nitrogen supply unit for supplying nitrogen to interior of the active heating chamber under controlled operation of the control unit to maintain anaerobic condition in interior of the active heating chamber during thermal decomposition of the biomass. The control unit is used for controlling operation of the water supply unit to supply water in the heating chamber in order to increase specific surface area of the thermal decomposed biochar, and controlling operation of the heating unit to heat the heating chamber for thermally decomposing biochar. The water supply unit is used for supplying water interior each of the heating chambers. The control unit is used for controlling operation of the water supply unit to supply vaporized steam condition under residual heat of the heating chamber to complete the operation. The control unit is used for controlling operation of the functional chemical supply unit and the oxygen supply unit to supply oxygen and solution of zinc salt into the active heating chamber to grant adsorption capacity of the increased specific surface area biochar. The inside each of the heating chamber includes at least one nozzle unit connected to the water supply unit, for spraying water on surface of the biochar.