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<p>The top-submerged-lance (TSL) smelting is a complex multiphase and multifield system, and it is not easy to achieve efficient coupling solutions for all the physical fields involved in the multiphase flow, transport, and reaction processes in the furnace. A key-field-coupling method was developed to couple the multiple factors in the TSL smelting process in this work and is expected to provide a useful tool for the simulations of other pyrometallurgical units dealing with multiple-complex-related fields. The multiphase fluid flow in the TSL furnace consists of the compressible gas flow in the lance and the gas–matte–slag multiphase flow in the bath. In the simulation, the high-speed gas in the lance is set as a compressible gas, and the effect of the molten bath heating on the motion of the gas flow is taken into account, which is new in this work. A coupling calculation model of the single-phase flow of compressible gas in the lance and the variable temperature wall was constructed to investigate the single-phase flow in the lance, while a VOF multiphase model coupled with a realizable <i>k-ε</i> turbulence model was adopted to analyze the gas–matte–slag multiphase flow in the bath. The swirler in the lance plays a key role by providing higher velocity magnitudes and a wider stirring area to improve the mass transfer and reaction in the furnace. It is found that the gas flow at the lance exit exhibits a time-dependent, periodic variation with a period of about 0.00375 second with the new lance model setup. Three types of velocity profiles as the input condition in the simulation of the gas–matte–slag multiphase flow in the bath were tested; namely dynamic velocity distribution, which represents the industrial top-submerged lance with a swirler, and two other simplified cases representative of a lance without a swirler, <i>i.e.</i>, time-averaged velocity distribution and uniform velocity distribution. The dynamic velocity distribution based on the key-field-coupling method represents the velocity variation at the lance outlet to the furnace inlet. Through comparisons of the gas penetration depth, mean slag volume distribution, bubble behavior, and the velocity field, the dynamic velocity distribution is determined to best represent the multiphase flow characteristics in the TSL smelting process. The results of this work verify the advantages of a swirler in the top lance and also point to the possibility of optimizing the swirler for the best performance.</p>

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Simulation of Copper Smelting Furnace with a Top Submerged Lance Based on Key-Field-Coupling, Part 1: Multiphase Fluid Flow

  • 期刊论文

  • 发表日期：

    2025年1月30日

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  • Xiaoyi Cai,
  • Wei Wang,
  • Hongliang Zhao,
  • Fengqin Liu,
  • Chao Lv,
  • Hong Yong Sohn

摘要

The top-submerged-lance (TSL) smelting is a complex multiphase and multifield system, and it is not easy to achieve efficient coupling solutions for all the physical fields involved in the multiphase flow, transport, and reaction processes in the furnace. A key-field-coupling method was developed to couple the multiple factors in the TSL smelting process in this work and is expected to provide a useful tool for the simulations of other pyrometallurgical units dealing with multiple-complex-related fields. The multiphase fluid flow in the TSL furnace consists of the compressible gas flow in the lance and the gas–matte–slag multiphase flow in the bath. In the simulation, the high-speed gas in the lance is set as a compressible gas, and the effect of the molten bath heating on the motion of the gas flow is taken into account, which is new in this work. A coupling calculation model of the single-phase flow of compressible gas in the lance and the variable temperature wall was constructed to investigate the single-phase flow in the lance, while a VOF multiphase model coupled with a realizable k-ε turbulence model was adopted to analyze the gas–matte–slag multiphase flow in the bath. The swirler in the lance plays a key role by providing higher velocity magnitudes and a wider stirring area to improve the mass transfer and reaction in the furnace. It is found that the gas flow at the lance exit exhibits a time-dependent, periodic variation with a period of about 0.00375 second with the new lance model setup. Three types of velocity profiles as the input condition in the simulation of the gas–matte–slag multiphase flow in the bath were tested; namely dynamic velocity distribution, which represents the industrial top-submerged lance with a swirler, and two other simplified cases representative of a lance without a swirler, i.e., time-averaged velocity distribution and uniform velocity distribution. The dynamic velocity distribution based on the key-field-coupling method represents the velocity variation at the lance outlet to the furnace inlet. Through comparisons of the gas penetration depth, mean slag volume distribution, bubble behavior, and the velocity field, the dynamic velocity distribution is determined to best represent the multiphase flow characteristics in the TSL smelting process. The results of this work verify the advantages of a swirler in the top lance and also point to the possibility of optimizing the swirler for the best performance.