FIELD: steam generators. SUBSTANCE: according to invention, first evaporating heated surface 5, 9 and second evaporating heated surface 4 are installed in elongated lengthwisely gas duct 2 for hot gas of proposed steam generator. First feed pipeline 10 of feed water is connected to first evaporating heated surface 5, 9 at inlet, while second evaporating heated surface 8 is connected to low pressure drum at inlet and at outlet. Low pressure drum 7 is furnished with second feed pipeline 6 for feed water. First feed pipeline 10 contains heating surface 12a arranged inside gas duct 2, and second feed pipeline 6 is connected to place of connection between heating surface 12a and evaporating heated surface 5, 9 to first feed pipeline 10. Feed pipeline 10 feed pipelines 10 are provided with preparation points 47 and 46 for introduction and/or removal of chemicals for water preparation, thanks to which each evaporating heated surface 5, 9, 8 gets feed water specially conditioned as stated in instructions. EFFECT: enlarged operating capabilities, improved reliability. 8 cl, 3 dwg
