Today’s photo shows an indirect batch rotary kiln in the FEECO Innovation Center.
Indirect kilns heat solids to the point where a desired chemical reaction or phase change takes place. Unlike their direct-fired counterparts, indirect kilns are used when a material cannot come into contact with the combustion gases, and thus the heat is introduced to the outside of the drum shell via gas burners or electric heaters.
FEECO’s process experts regularly use the indirect batch kiln during thermal tests. The tests consist of heating a material to a hold temperature, with the goal of ultimately determining the maximum temperature that the feed can tolerate and the time it takes to do so. Samples are taken at regular intervals to measure the extent of reaction. In addition, several shell temperatures can be tested to determine the effect of temperature on reaction rate.
FEECO’s indirect batch rotary kiln has a diameter of 10.5” (0.27 m) and a heated length of 24” (0.61 m). It is generally filled to 8-10% volumetric loading. Dams are also located inside the kiln to keep the material within the heated zone.
The kiln shell is capable of reaching temperatures up to 1000 °C and is heated by a propane burner underneath the shell. Two thermocouples located near the shell in the furnace are used to measure the shell temperature. Two additional thermocouples are used to measure the bed and exhaust gas temperatures. Finally, the ends of the kiln can be sealed, and have an inlet for the purge gas and an outlet port for purge gas exhaust.
Interested in testing with FEECO’s indirect batch kiln? Contact a FEECO expert today!