In the heat of the rotary kiln is mainly formed in the rotary kiln combustion of pulverized coal in pulverized coal combustion, and in the process, and transfer effect, will form a large amount of heat, the different position of the rotary kiln, the material is chemically, and the absorption of heat.

(1) combustion analysis of pulverized coal

In general, the combustion of pulverized coal is at the top of the rotary kiln, after combustion, will form a large number of flue gas at the top of the rotary kiln, the flue gas temperature is relatively high, according to the length of the flame, to the analysis of rotary kiln flue gas temperature.

(2) heat transfer analysis of rotary kiln

In the analysis of the heat transfer of rotary kiln, analyze the main methods and coefficient of heat transfer can be through the transfer of the rotary kiln, the heat transfer in the rotary kiln, the heat transfer area is fixed, so, in the calculation of heat transfer problems of rotary kiln, the key is to calculate the coefficient of heat transfer.

1. Heat transfer form of rotary kiln

The pulverized coal in the combustion process, will produce a lot of smoke, the smoke temperature is relatively high, and will generally focus on the top of the rotary kiln, is the main source of heat in the rotary kiln, which can heat by radiation in the rotary kiln wall transfer, and can transfer heat to the material in the the rotary kiln wall, the heat transfer to the material it can be used in different ways, in the rotary kiln wall, mainly through the method of heat conduction, heat transfer to the outside of the cylinder, the external cylinder can by convection, heat dissipation, and can radiate to the surrounding environment.

2. Analysis of heat transfer coefficient

The heat transfer coefficient of the wall and material in the rotary kiln is mainly divided into the coefficient of the material in the unstable state and the heat transfer coefficient of the material covering the wall of the rotary kiln, and the two coefficients are added together so that the heat transfer coefficient can be obtained.

In the rotary kiln wall open, analyzed the heat transfer coefficient of material and gas, analyzed the heat transfer coefficient of flue gas, in order to obtain the convective heat transfer coefficient, flue gas and material and in the rotary kiln wall is an open condition, can form a strong effect of heat transfer, the heat transfer coefficient is relatively large.

In the rotary kiln will produce a large amount of radiation, the radiation coefficient can be analyzed, the heat transfer coefficient of radiation in rotary kiln was simplified, in order to obtain a closed cavity absorption flue gas, as well as on the surface of gray body will form a radiation heat transfer coefficient, and then transported by network simulation, combined with thermal balance the radiation heat transfer coefficient equation.

The analysis of the heat transfer coefficient of the outer surface of rotary kiln can be done by analyzing the heat dissipation of the surrounding environment, and then analyzing the way of convection heat transfer. In the analysis of the convection heat transfer coefficient, the flue gas which can not be rotated in the rotary kiln can be analyzed first, and then the heat transfer coefficient is analyzed according to the forced convection.

(3) chemical reactions produced by materials in rotary kiln

In the process of production of cement, mainly to lime, clay and siliceous material and iron together, and then ground into powder in high temperature conditions, by burning, the chemical reaction, so as to form cement clinker. In the rotary kiln, the chemical reaction can be divided into four different zones, respectively, with decomposition of transition zone, burning and cooling, in the cooling zone, the probability of chemical reaction is relatively small, chemical reaction occurred in the other three delegates will. The chemical reaction in the rotary kiln, the four kinds of chemical substances, so different, so the reaction mechanism is relatively complex, so, in the process of each zone were analyzed in the reaction is difficult, and should use simple calculation method, the chemical reaction can be evenly distributed.