For the selection and design of a rotary kiln system, it’s required to master its thermal characteristics and learn the relative knowledge of rotary kiln from the view of production technology. 

In a series of rotary kiln device design, the adaptability of the rotary kiln and the materials to be calcined should be considered firstly. The material balance and heat balance are the foundation for the design of rotary kiln while the index of the output per unit area is one important basis for the design of rotary kiln.

The ratio of the length and diameter of the rotary kiln (L/D) can reflect the thermal characteristics of rotary kiln better. As the length and diameter of the rotary kiln have a direct influence on the effect of the calcination, there exist some problems such as the different convection heat transfer conditions and the different effects of low temperature heat transfer.

Along with the development of the active lime calcination process, the type of kiln widely use the shorter shell length and bigger shell diameter in the selection of the type of rotary kiln for active lime calcination, according to the property of the active lime product.

For example, the first set of rotary kiln with vertical preheaters and cooler in China, imported from German company Krauss Maffei in 1978, used the 20 - 40 mm thickness and the MRST37.2 series number of the steel plate as the material, in the selection of its shell material. The kiln and the big gear ring are connected by a steel spring plate according to the needs of heating and expansion.

For the installation of the shell, it’s required to design based on the basic requirements. The best condition is that when the angle between the center line of the shell and the centre line of support rollers is 60°. The number of support roller should be set up to the length and the material requirements of the shell.

According to the features of lime products and the need of calcination, there is no feed end ring in the rotary kiln but rely on the on both ends of the kiln shell to ensure the thickness of the material. The movement of material in the kiln is realized by the installation inclination of the shell in the rotation of the shell from the high point to the low point. Inclination of the shell usually refers to the ratio of increasing kiln axis and kiln length, which always taking the sine Siaɑ of the slash angle. When the inclination of shell is 3%, the slant angle is 1°43‵.

The movement form of material in rotary kiln is the material in the position of A rises slowly along with the kiln wall due to the friction when the material rotates with the shell, not considering the sliding of material particles in the kiln wall & internal material layer and the impacts of the particle size. When the angle formed by the material surface and the horizontal surface equals to the stationary horn of the material, then the material particle will slide down along the material surface in the gravity function. Since the rotary kiln has a certain slope, the, the material in A point will not fall in the original position but move forward to C point, then move from C point to D point and fall into E point for the second time. Keep moving forward in this way is the ideal state of the material rotation in the shell.