Analysis Of Internal Heat Transfer Characteristics And Flow Field For Cement Rotary Kiln

Rotary kiln is one of the important equipment to produce industrial cement. In orderto improve the production efficiency, reduce consumption and achieve the purpose ofsaving energy, the rotary kiln internal gas-solid two-phase flow and combustion heat flowfield is studied by numerical simulation to optimize the process parameters and to selectsuitable burner, the reference for the structure design of the rotary kiln can be provided.In this thesis, a cement rotary kiln with diameter of Ф4.8m, length of74m and dailyoutput of5000t is taken as a research object. With the actual parameters as modelinganalysis conditions, the furnace turbulence flow heat transfer process and pulverized coalcombustion process are analyzed in this thesis by using the method of numericalcalculation, and the control parameters such as secondary air temperature are optimized,rotational flow angle and inside&outside air volume ratio and so on.The turbulent flow mathematical model, the mathematical model of the pulverizedcoal combustion and radiation heat transfer model are analyzed and selected in this thesis,the boundary conditions and initial conditions of pulverized coal combustion process areset in according to the actual operating conditions, and the flow field distribution ofrotary kiln can be obtained by simulative calculation, furthermore, the initial condition ofmaterial-kiln wall-flue gas heat transfer model will be use the result to simulate thedivision of working tape in the rotary kiln. The results the outer wall of kiln and underpractical conditions are basically the same. In that way, the selected mathematical modelin the numerical calculation, boundary conditions and initial conditions can be provedcredible.In the premise of burner under the given, the pulverized coal combustion process ofthe Ф4.8×74m cement clinker kiln is simulated and calculated according to the actualworking conditions. By means of changing the secondary air temperature, rotational flowAngle and inside and outside air volume ratio, a set of controlling parameters which getthe pulverized coal combustion efficiency improving and the furnace temperaturedistribution justified can be find out, even the secondary air temperature is1100K, the air surplus coefficient is1.3, the inside and outside air volume ratio is0.8, the rotational flowangle is30°. The initial condition of adding materials and supplies and the whole modelof rotary kiln wall is defined according to the optimization of the parameters, thedirection of the working tape along the rotary kiln axis is simulated and calculated.