Rotary Kiln Dryer

Rotary kiln dryer is a dryer machine disposal massive materials. It is widely used in metallurgy, construction, light industry and so on. In the chemical industry, most of the chemicals use rotary kiln dryers like ammonium sulfate, sulfide, and powder, ammonium nitrate, urea, oxalic acid, calcium carbonate, calcium magnesium phosphate fertilizer, normal superphosphate calcium, heavy superphosphate and sodium melamine. Rotary kiln dryer can generally used in granular material. It can also adapt to viscous paste or high moisture content materials by drying them with dry materials. Moisture content rate of materials is generally about 3-25%  while the moisture content of production is about 0.5%.

Rotary Kiln Dryer Working Principle

During the drying process, wet materials are sent to the hopper by belt conveyor or bucket elevator. Then be put into feed end through the charger. The inclination of the feed pipe is bigger than the material’s natural inclination to ensure the material’s flow into the dryer successfully. The tumble dryer cylinder is a rotating cylinder slightly inclined from the horizontal line.

The material is added from the higher end, the heat carrier enters from the lower end, and comes into countercurrent contact with the material, and the heat carrier and the material flow into the cylinder together. As the cylinder rotates, the material moves to the lower end under the effect of gravity. During the forward movement of the wet material in the cylinder, the heat is directly or indirectly obtained by the heating medium, so that the wet material is dried, and then sent out by a belt conveyor or a screw conveyor at the discharge end. A copy board is installed on the inner wall of the cylinder, and its function is to copy and scatter the material, so that the contact surface between the material and the air flow is increased to increase the drying rate and promote the material to advance. The heating medium is generally divided into hot air and flue gas. After the heating medium is passed through the rotary drum dryer, a cyclone dust collector is generally required to capture the material in the gas. If you need to further reduce the dust content of the exhaust gas, you should also discharge it after passing through a bag filter or wet dust collector.

Rotary Kiln Dryer Structure

  • Cylinder: Round tube shape made of steel plate. The diameter is 0.8m ~ 4mm or more, and the length is 2 ~ 50m.
  • Dispersion of materials — copying plate: copying plate is set to make the material fully dispersed in the dryer so that the hot air and the material are in full contact. There are many forms of copy board, which are suitable for the material and drying stage.
  • Wheel hub and supporting roller: It is a supporting part that can withstand the rotation of the barrel. It is made of cast iron, steel and cast steel. It can be supported at 2 points, 3 points or 4 points according to the length of the barrel.
  • Drive: There are friction drive, chain drive, and gear drive, depending on the power.
  • Air sealing device: The drum and the fixed part must be sealed to prevent hot air from leaking.