Numerical Simulation And Optimization Of Multiphase Flow In Bottom Blowing Lead Smelting Furnace

ABSTRACT:The process of the lead smelting using bottom blowing bath, which is China’s independent intellectual property rights of a new generation of advanced lead smelting process. And the bottom blowing lead smelting furnace is the key equipment for it. The multiphase flow behavior of high temperature melt with oxygen-enriched air is essential to the process in the furnace. In this dissertation, the numerical simulation method is used to systematic analysis and optimize the multiphase flow behavior in the furnace conducted to improve the process metallurgical reaction intensity and energy efficiency.In this paper, taken the bottom blowing lead smelting furnace as the prototype, reasonable simplified assumptions is used to establish the physical model of the melting furnace, and the VOF multiphase flow model and Realizable k-ε model is selected to simulate the multiphase flow behavior in the furnace. The influence of the key structural and operating parameters of the smelting furnace to the process is obtained by univariate analysis, such as oxygen lance inclination, the pool depth oxygen lance diameter and oxygen lance spacing. In order to get each factor optimal combination, orthogonal experimental design and matrix analysis method is used to analysis the process. The main conclusions are drawn as follows:(1)The physical and mathematical model of bottom blowing lead smelting furnace is established by reasonable simplified assumptions, and appropriate grid is meshed by grid independence check. Water model test method is used to verify its reliability.(2)The numerical simulation study of the reference conditions shows that:the average residence time of the oxygen-enriched air in the bath is0.35s. The average fluid movement of the molten pool area speed is0.18m/s, and the average turbulent kinetic energy is0.092m2/s2. The average gas floating speed is4m/s. The active reaction zone is located in the upper of the oxygen lance area, the bath reaction zone’s bath gas rate is5.02%. The smelting furnace melt splashes phenomenon is very serious, mainly concentrated in the upper part of the oxygen lance area.(3) The analysis of multi-factor and multi-objective optimization by orthogonal experimental design and matrix method shows that:the optimal combination of the key structural and operating parameters in the bottom blowing lead smelting furnace is oxygen lance inclination15°, pool depth1420mm, oxygen lance diameter25mm, and oxygen lance spacing1300mm. The factors affecting the bottom blowing lead bath smelting process has the following sequence:oxygen lance diameter> pool depth> oxygen lance spacing> oxygen lance inclination.