For a mid-speed coal mill system

the cold air flow is very high while the temperature at the mill exit can't be increased due to the bearing temperature's limiting.Therefore

a hot primary air mixing with air-coal mixture system is presented.Thermal simulation is conducted for this system using the commercial EBSILON software.The air temperature at the mill entrance

cold air flow

flu gas exit temperature

mill vane velocity

mill exit velocity

and air-coal velocity after mixing with hot primary air are all simulated.By using the system presented in this paper

the cold air flow decreases

the flue gas exhaust temperature decreases

and the air-coal mixture's velocity and temperature after mixing with hot primary air increase as the mill almost running under the original condition.Based on the simulation results

the hot primary air mixing with air-coal mixture system is technical practicable.