Indirectly heating rotary dryer

An indirectly heating rotary dryer comprising

• a rotating shell having a first end and a second end and an inner space, wherein said rotating shell rotates about a central axis thereof and is capable of feeding a material to be dried from said first end to said second end, where it is discharged;
• a feed unit for feeding the material to be dried into the first end of said rotating shell, said feed unit having a feed nozzle for receiving said material to be dried;
• a plurality of heating tubes for heating the material to be dried in the rotating shell wherein said plurality of heating tubes are located within said rotating shell and are oriented substantially parallel to the central axis of the rotating shell;
• and
• a plurality of partition walls, which are arranged in the rotating shell so as to partition the inner space of the rotating shell into a plurality of smaller spaces along the central axis of the rotating shell;
• a heat medium inlet pipe attached to a rotary joint for supplying a heat medium to the plurality of heating tubes and a heat medium outlet pipe for draining said heat medium after it has been circulated through the plurality of heating tubes;
• wherein the plurality of heating tubes is arranged separately in the plurality of small spaces between the end plates at both ends of the rotating shell;
• wherein the plurality of partition walls are plates;
• wherein the material to be dried is poured into first end of the rotating shell through the feed nozzle of the feed unit and is dried as it contacts the plurality of heating tubes;
• wherein the material to be dried poured into the rotating shell is distributed into the plurality of smaller spaces;
• and
• wherein the rotating shell is installed at a downward pitch from said first end to said second end, so that the dried material can be continuously moved from the first end of said rotating shell to a discharge opening at the second end of the rotating shell.