Currently, approximately 85% of the world's calcined coke is produced using rotary kilns. Rotary kilns burn solid carbon feedstock, unlike canister kilns, where the calcined material is heated indirectly, while in rotary kilns, it is heated directly by flames.
A calcining rotary kiln consists of a calcining kiln (large kiln) and a cooling kiln (small kiln). The large kiln consists of three parts: the kiln head, the kiln body, and the kiln tail. The kiln body size varies depending on production needs. Smaller rotary kilns have an inner diameter of only about 1 meter and a length of about 20 meters; larger rotary kilns can have an inner diameter of 2.5-3.5 meters and a length of 60-70 meters.
Cylinder.
The cylinder is a long, rolled cylinder made of thick steel plate, welded or riveted together, and lined with refractory bricks. The cylinder rests on rollers with the aid of a wheel rim. The wheel rim is a cast steel ring mounted on the outer shell of the kiln. The kiln body rotates on the rollers with the help of the wheel rim. To prevent the drum from sliding off the rollers, baffles are installed on both sides of each wheel flange.
Kiln Head.
The end where the calcined material is discharged and the fuel is injected is called the kiln head. Kiln heads are either fixed or movable. They are lined with refractory bricks and equipped with fuel nozzles and observation holes. Calcined material falls into the cooling kiln through a discharge hole at the bottom of the kiln head. A sealing ring is installed at the junction of the kiln head and the drum to prevent outside air from entering the kiln.
Kiln Tail.
The end where raw materials are added and exhaust gases are discharged is called the kiln tail. The kiln tail is often made movable and also lined. Material is continuously added from above the kiln tail via an electromagnetic vibrating feeder. The kiln tail is connected to the chimney flue. The lower part of the kiln tail is also connected to the ash settling chamber. A sealing ring is also installed at the junction of the kiln tail and the drum.
Cooling Kiln.
The cooling kiln is a steel cylinder tilted in the opposite direction to the main kiln. Its support and transmission mechanisms are similar to those of the simplified kiln. A water spraying device is installed outside the cooling kiln to cool the rear materials. A certain number of lifting plates are also installed in the cooling cylinder, and a sealing device is installed at the discharge end.