Abstract:In view of the fact that in a practical operation of a coal-fired power plant,the higher cold air rate of medium speed mill coal pulverizing system causes the exhaust gas temperature to rise,which leads to the decrease of the boiler efficiency,a thermal equilibrium calculation model of the medium-speed mill is established.Through calculation and analysis,it can be seen that the inlet and outlet temperatures of the mill are greatly affected by the moisture content in the coal,and when the moisture of the coal increases by 1%,the inlet air temperature of mill will increase by 12℃.Therefore,under the premise of ensuring the safety of the unit,by reducing the amount of cold air to increase the outlet temperature of the coal mill that is to increase the hot air temperature at the inlet of the coal mill,the tail flue gas heat can be fully utilized to improve the boiler thermal efficiency.This method does not require any operating costs and equipment investment,so the economic benefit is very significant.