Oxygen-free lignite drying system

The utility model discloses an oxygen-free lignite drying system. The system is used for predrying lignite and can directly dry lignite with 30 percent to 50 percent of water content until the water content is 5 percent. The structure of the system is as follows: the system comprises a feeder, which is connected with a superheated steam internal-heating fluidized bed drier, a built-in heat exchanger of the superheated steam internal-heating fluidized bed drier is connected with a flue gas heat source, and the bottom of the superheated steam internal-heating fluidized bed drier is connected with a superheated steam heat source; the discharge end of the superheated steam internal-heating fluidized bed drier is connected with a finished product area, an air outlet is connected with at least one stage of deduster, part of dedusted tail gas is recovered, and the other part of the tail gas is sent back into the bottom of the superheated steam internal-heating fluidized bed drier. The system has the advantages of simple technique, short flow, continuous operation and remarkable energy-saving effect.