Abstract: Raw coal in Wangcun preparation plant has obvious characteristics such as high ash content, fine particle size and high moisture content.The existing air separation system is closed because of its low adaptability and low efficiency.In order to resume the separation system and improve the calorific value of products, we analyze the coal quality of raw coal, and study the process of depowder and middle coal separation process.50-3 mm main re-separation process without 3 mm powder coal was finally adopted.Combined with the existing production facilities, the combined cross screen with relaxation screen is adopted to ensure the flexible and adjustable particle size of powder removal, with the open-circuit re-separation of middle coal to improve its capacity and separation accuracy.The practical production results show that the yield of clean coal is equivalent to that before transformation, the calorific value of the product is increased from 4 208 kcal/kg to 4 517 kcal/kg, and profit increases to 33.56 million yuan.The adaptability of the system to raw coal is significantly enhanced, and the transformation process conforms to raw coal, and expected effect is achieved.