Numerical Simulation And Structure Optimization Of Vanadium Extraction Rotary Kiln Combustion Process

In recent years, vanadium has been one of the most important strategic reserve resources.Vanadium from vanadium containing shale is an important way to obtain vanadium products inChina. Roasting process is an important aspect, and rotary kiln can be applicable in roasting.Firstly, the paper analyzes the mathematical models used in the numerical simulation of thecombustion in rotary kiln. Multiphase flow model, turbulence model, combustion model,radiation model, NO_xgeneration model were included in the mathematical models. A set ofmathematical models for combustion process were established in rotary kiln. Particle transportmodel, k-ε model, Eddy Dissipation model, P1model were selected.Secondly, the heat balance calculation was carried out on the roasting process of stone coalin rotary kiln. Two different groups of the fuel and air velocity were obtained. Through CFX,numerical simulation method was used for studying the combustion performance of rotary kiln.By analyzing two sets of simulation results, the most suitable fuel speed was4.04m/s, and themost suitable air speed was3.88m/s.In addition, the combustion performance of rotary kiln was studied by numericalsimulation. The distribution of temperature field, flow field, the component field, the particletrajectories and NO_xconcentration in rotary kiln were obtained in the normal operating state. Theresult show that temperature distribution and the position of high temperature agree well withmeasurement in the site. The distribution trend of flow field and NO_xis correct. The obtainedparticle trajectories results in this numerical simulation are consistently with previous experimentresults in some degree. This is also shows that using numerical simulation method is correct.Finally, by changing the structure of rotary kiln, the important impaction to the gastemperature field, NO_xconcentration, gas velocity and particle trajectories were studied. And theresults show that the temperature distribution is uniform and the length is appropriate in theroasting area of the expanded structure rotary kiln. And NO_xconcentration is lower in thecombustion area than other structure rotary kilns. Particle trajectories are the most abundance ofthe expanded structure rotary kiln, which is more favorable for the roasting process of stone coal.