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Yanyu Zhao, Wei Chen, Shusen Cheng, and Lifeng Zhang, Mathematical simulation of hot metal desulfurization during KR process coupled with an unreacted core model, Int. J. Miner. Metall. Mater., 29(2022), No. 4, pp.758-766. https://dx.doi.org/10.1007/s12613-022-2425-4
Yanyu Zhao, Wei Chen, Shusen Cheng, and Lifeng Zhang, Mathematical simulation of hot metal desulfurization during KR process coupled with an unreacted core model, Int. J. Miner. Metall. Mater., 29(2022), No. 4, pp.758-766. https://dx.doi.org/10.1007/s12613-022-2425-4
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耦合未反应核模型的KR铁水脱硫过程数值模拟

摘要: 硫元素对绝大多数钢材的机械加工性能、抗腐蚀性能和磁性能等均有显著恶化作用,如何将钢中硫元素高效稳定的去除以及精确的控制仍然是冶金过程的研究热点。本研究通过建立耦合的湍动能-湍动能耗散率湍流模型(turbulent kinetic energy-turbulent dissipation rate, kε)、多相流模型(volume-of-fluid, VOF)、硫元素用户自定义标量传输模型(user-defined scalar, UDS)、离散相(discrete-phase model, DPM)脱硫剂运动模型及未反应核脱硫动力学模型,研究了实际机械搅拌(Kanbara reactor, KR)铁水预处理过程多相流场分布、脱硫剂运动和分散以及脱硫动力学。通过不同时刻下硫含量预测值与实际检测值的对比证明了目前脱硫数值模型的准确性以及确定了硫元素通过扩散边界层到达脱硫剂表面的外扩散为目前工况下的脱硫动力学限制性步骤。研究结果表明,脱硫速率常数随着搅拌桨转速的增大而增大,转速110 r/min下脱硫速率常数是30 r/min的三倍左右;铁水中平均硫含量随时间变化基本呈现指数函数的分布规律。脱硫剂加入完毕以后,脱硫速率降低速率也随时间逐渐下降,且转速越大,脱硫速率降低的越快;提出了KR搅拌过程湍动能耗散率ε与脱硫速率常数β之间的一般关系式 \beta = 0.00688 \cdot \varepsilon ^0.265 ,进而得到了应用范围更广的硫含量与湍动能耗散率ε及反应时间t的关系式 \% \textS = \% \textS_0 \cdot \texte^ - 0.00688 \cdot \varepsilon ^0.265 \cdot t

 

Mathematical simulation of hot metal desulfurization during KR process coupled with an unreacted core model

Abstract: A three-dimensional mathematical model was established to predict the multiphase flow, motion and dispersion of desulfurizer particles, and desulfurization of hot metal during the Kanbara reactor (KR) process. The turbulent kinetic energy–turbulent dissipation rate (k–ε) turbulence model, volume-of-fluid multiphase model, discrete-phase model, and unreacted core model for the reaction between the hot metal and particles were coupled. The measured sulfur content of the hot metal with time during the actual KR process was employed to validate the current mathematical model. The distance from the lowest point of the liquid level to the bottom of the ladle decreased from 3170 to 2191 mm when the rotation speed increased from 30 to 110 r/min, which had a great effect on the dispersion of desulfurizer particles. The critical rotation speed for the vortex to reach the upper edge of the stirring impeller was 70 r/min when the immersion depth was 1500 mm. The desulfurization rate increased with the increase in the impeller rotation speed, whereas the influence of the immersion depth was relatively small. Formulas for different rotation parameters on the desulfurization rate constant and turbulent energy dissipation rate were proposed to evaluate the variation in sulfur content over time.

 

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