The three barrel dryer has made a great breakthrough and innovation on the basis of the structure of the traditional rotary dryer. From the drying mechanism, the exchange of material and hot gas flow is more fully, more scientific and reasonable, and the various thermal indicators have reached the leading level in China. From the practical application, the structure is more economical, less energy consumption, easy to maintain, and the outlet temperature is suitable, which can ensure the safe, continuous and reliable operation of subsequent dust removal equipment.