FIELD: preheating of feed water and primary air by heat contained in boiler waste gases. SUBSTANCE: device has rotary heat transfer unit 3 where waste gas (AG) escaping from boiler 1 where hydrogenous coal is burnt is cooled; heat of waste gas (AG) is used for heating air (VL) required for burning which is introduced in boiler 1. Heat motion unit 5 is provided in parallel with heat-transfer unit 3. Primary air (PL) is preheated by means of heat of waste gas (AG1) escaping from heat transfer unit 3 which is shunted with heat exchanger 14 by means of bypass 13. Heat exchanger 14 may be loaded with waste gas (AG). Feed water (KSW) flows in heat exchanger 14. Feed water is heated by waste gas (AG). Additional heat exchanger 18 may be directly connected to heat motion unit 5. Heat exchanger 18 may be used for heating the waste gas (AG4) escaping from device 21 for elimination of sulfur in flue gases for loading smoke stack 22. EFFECT: enhanced efficiency. 2 cl, 3 dwg
