Rotary Dryer and rotary kilns are very similar in design and are closely related to dryers. The major difference is that dryers only have an outer metal shell, whereas rotary kilns have refractory bricks for insulation. Each type of equipment in this page has sections on general information, information about equipment design, usage examples, and advantages/disadvantages.

Rotary Kilns

Kilns are furnaces used for ceramic or brick heating, causing moisture and organic materials to evaporate. Kilns are heated by horizontal space burners with gas, liquid, or solid fuel.

A rotary kiln is a cylindrical steel tube lined with insulating brick. The large ones can be as long as 120m with a diameter of 6m. The kiln turns on a horizontal axis at an angle of 2 to 3 percent to the horizontal.

Charge, or material to be heated, enters tunnel kilns on trays or trucks at one end, contacts the gas, and exits at the other end. The trays or trucks move on tracks or monorails. Heating is provided by reheat coils, and large propeller-type fans circulate the combustion gases. The picture below shows a tunnel kiln.

The Rotary Dryer

Despite the introduction of new technology, the long established Rotary Rotary Dryer is still widely regarded as the workhorse of many process industries. The robust yet simple construction combines flexibility with reliability, enabling this type of dryer to handle a vast range of materials and to operate continuously under the most arduous conditions. The design also permits the use of the highest possible drying temperatures and in contrast to other dryers is not sensitive to wide variations in material size, moisture content or throughput.