TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Method: The biomass is crushed during or after drying. The biomass is compressed, preferably pelletized after drying and crushing in the form of pieces. The heat exchange is carried out with the refrigerant through an evaporator, which is operated with the refrigerating machine, which supplies the refrigerant to the evaporator, where the refrigerant is R407c or nitrogen. The processing air is supplied to a second heat exchanger downstream the first heat exchanger to increase the processing air temperature. The second heat exchanger supplies the processing air into an exhaust gas heat exchanger of the heating device via a water circulation. Preferred Components: The air dryer is provided with connections for supplying and discharging the processing air, a condenser for cooling and drying the processing air and the first heat exchanger for heating the processing air, where the heat exchanger is arranged downstream the condenser. The first heat exchanger is operated by a compressor refrigerating machine, where the heat exchanger is connected with the high temperature side connection of the compressor for supplying the refrigerant. The air dryer exhibits the second heat exchanger downstream the first heat exchanger for heating the processing air. The air dryer is located in a housing separated from the fuel dryer. The apparatus comprises a cylindrical dryer drum, the connections for supplying and discharging the processing air and closeable openings for filling and removing the biomass, where a rotor with grippers to move the biomass is arranged inside the drum that is connected via a rotational drive for rotating the rotor, and drying and crushing steps of the biomass are carried out simultaneously during the operation. The rotor is arranged coaxially within the dryer drum, and the gripper with radially extending arms is distributed on a longitudinal axis. The gripper is combed with rakes mounted at an inner side of the drum during rotational movement of the rotor. The filling opening is designed as a notch in an upper side shell surface of the dryer drum, and/or the opening for removing is designed as a notch in a lower side shell surface. The connectors for supplying and discharging the processing air are formed respectively at a front side of the dryer drum, so that the dryer drum is axially perfused with the processing air. The opening for removing the dried and crushed biomass is connected with the device for compressing the biomass in the form of pieces via a packed bed. The cylindrical shell exhibits an additional opening for supplying the biomass into the operating chamber of the cylinder.