SIMULATION OF THE BURNING PROCESS AND OF THE HEAT TRANSFER IN THE FLAME AREA OF THE ROTARY KILN

This paper presents a mathematical model for the heat transfer in the clinkering area of the rotary kiln. This problem can be solved in several ways. One simplistic approach would be to know the flame temperature in order to compute, among other secondary parameters, the temperature profile of the material. Another much more practical option is to know (to set) the temperature profile of the material over the length of the clinkering area of the rotary kiln, that further could be used to calculate the gas and kiln wall/shell temperature. In this study it was consolidated this last alternative which requires the heating curve of the material (it is known/given the distribution of the material temperature in the rotary kiln, as necessary to obtain clinker quality). We then moved forward by implementing a broader approach, i.e. by assuming different amounts of fuel allocation over the length on the clinkering area; this distribution could be correlated with flame shape. Several coating width values were also included in simulation as an input parameter, thus contributing to broadening the options and to increase the realism level. The model used a series of assumptions, limitations and simplifications. They are due to the complex nature of processes taking place in this area and are compulsory because the clinkering area could be considered independent and having a fixed length only under ideal conditions! In real life, complex interactions of material and energy with other parts of the clinkering plant can be easily identified.