Coal mill is the main equipment that affects the economy of coal-fired power plant. This paper introduces that the fineness of pulverized coal in a power plant is coarse

which results in insufficient combustion of pulverized coal

low thermal efficiency of the boiler and failure to reach the guaranteed value. In order to improve the operation economy of coal-fired power plants

the reasonable operation mode is determined by optimizing and adjusting the parameters such as the speed of the separator

the coal level

the ventilating capacity and steel ball volume of the double-in and double-out ball mill

the fineness of the coal powder is reduced to the optimal value

the boiler efficiency and economy are improved.