Research Findings and Development Suggestions of Rotary Kiln

AUTHOR: admin DATE: 27 Jul 2012 11:12:13

Against the backdrop of automatic control application and research project, Hongxing Machinery conducted simulation research of the thermotechnical process of the rotary kiln with the rotary kiln produced by our company as the research object and we mainly carried out the following work and reached the related conclusions:

rotary kiln

1. On the basis of the thermal equilibrium calculation of this machine, we analyzed the heat-transfer process of the internal section of it, established a two-dimension model of the heat-transfer process of the kiln and calculated the distribution situation of the temperature of the kiln wall along the radial direction and the changing condition of the surface temperature inside the kiln with the change of time, and the result shows that when the kiln is working on a normal condition, the radiation loss of the outside kiln remains basically unchanged. If considering the process of the thermal storage and heat release cycle as a whole, the heat transfer process inside the kiln can be simplified as a steady-state transfer. This research finding provided theoretical basis for simplifying the heat-transfer mathematical model of the rotary kiln.

2. We conducted a numerical simulation to the heat transfer of the gas and kiln wall to the materials using multiphase flow theory, calculated the two-dimension distribution condition of the temperature of the materials on the section when the diameter of the particles that are sent into the kiln is even. The numerical simulation finding shows that on various working conditions, the temperature distribution of the materials on the section is similar, except that the temperature of part material particles on the external surface which get in touch with the gas and the kiln wall is higher than that inside the kiln. This research finding provides theoretical basis for the establishment of one-dimension heat-transfer model for the calculation of the temperature distribution of the gas and materials inside the kiln.

3. We built a one-dimension online simulation model, and based on the heat balance test and using the on-spot online test parameter as the border or the initial condition, we calculated the distribution condition of the temperature of the gas and the materials inside the rotary kiln along the axial direction of the kiln, analyzed the influencing law of the parameter changes such as excess air ratio, fire coal amount and coal mixing amount on the temperature distribution and examined the model using the on-spot test data.

4. We applied the on-line simulation result in the production process, built a rotary kiln online simulation system in order to diagnose the firing condition inside the machine and providing foundation for the optimum operation of the machine.

The simulation research work of the thermal process of the rotary kiln by experts of Hongxing Machinery is very limited, so we proposed further suggestions here:

1. When conducting research on the multiple phases flowing and heat transfer inside the rotary kiln, we made several assumption for the convenience of calculation, so we suggest that we should gradually consider the influences of various factors in the future research.

2. Make further improvement to the mathematical simulation research on the multi-phase flow inside the machine. And we suggest that we should consider the influences of the temperature changes of the kiln wall circumference on the temperature distribution of the materials when calculating the one-dimension simulation model.