Abstract: A dryer for removing moisture from wet fine particles, such as coal, comprising an insulated stationary cylinder in which an open-ended metallic cylindrical tube is rotated, coaxially in an essentially horizontal position. Wet particles are introduced in said open end while hot air is circulated between the stationary cylinder and the tube.Substantial improvement in the overall efficiency is obtained by recirculating some of the spent products of combustion into the rotary drying cylinder as well as in a preheater or heat exchanger to heat the air used for combustion.

Abstract: A dryer for removing moisture from wet fine particles, such as coal, comprising an insulated stationary cylinder in which an open-ended metallic cylindrical tube is rotated, coaxially in an essentially horizontal position. Wet particles are introduced in said open end while hot air is circulated between the stationary cylinder and the tube. Metallic balls or the like contained in the rotating tube are interspersed in the wet mix. Perforated fins and baffles extend from the outer wall of the tube to aid in transferring heat, by conduction, to the tube and metallic balls to evaporate the moisture before the coal is discharged at the opposite end through a screen section of the tube. Additives may be introduced into the wet mix to coat the dried coal particles to prevent dust or prepare the mix for pelletizing or briquetting.

Abstract: A method and apparatus for drying wet coal granules or particles by introducing a liquid petroleum or coal derivative into the wet granular material, either before feeding into a dryer, or while it is fed, or at some point along the dryer cylinder embodying my prior patent 3,401,923. Thus the danger of explosion or obnoxious dust resulting from dry coal is eliminated and the calorific value of the coal is greatly increased. A modification of the air lock shown in my prior U.S. Pat. No. 3,401,923 is also made for improving the passage of heated particles into the housing.