DRYING METHOD AND DRYING SYSTEM OF BROWN COAL USING FLUE GAS RECIRCULATION Russian patent published in 2024 - IPC F26B20/00 F26B21/04 F26B23/02 

FIELD: technological processes.

SUBSTANCE: group of inventions discloses a drying method and a system for drying brown coal using flue gas recirculation. Method comprises: removing recirculating flue gas from the tail of the boiler as a dryer for performing a first drying step of high moisture brown coal; supply of hot primary air for the second stage of drying of preliminarily dried brown coal, while the pre-dried brown coal is subjected to coal milling and grinding in the coal milling and grinding unit; transferring, using hot primary air, obtained dust of dried and crushed brown coal and its supply to burner for combustion in boiler furnace; and performing coal milling and grinding for the pre-dried brown coal using a grinding system with a medium speed mill as a coal milling and grinding unit. System comprises: a flue gas recirculation unit, an air supply unit, a brown coal drying unit and a coal milling and grinding unit. According to present invention, boiler flue gas is discharged to perform preliminary drying of brown coal in order to reduce moisture of coal, so that the remaining moisture in the coal corresponds to the range of the drying capacity of the grinding system with a medium speed mill, and therefore for boiler for brown coal of high moisture content it is possible to choose more stable and reliable grinding system with mill of medium speed according to invention—boiler for brown coal of high moisture content.

EFFECT: inventions shall provide favorable conditions for more stable, efficient and less polluting use of brown coal resources.

8 cl, 1 dwg