铜精炼炉的CFD数值模拟优化

CFD-simulation as a tool for system optimization based on the example of a copper refining furnace

本文用CFD数值模拟对某厂的铜精炼炉生产进行优化。通过改进还原剂的加入方式和混合方式,达到提高还原剂利用率的目的。利用率的提高可减少还原剂的用量,还原剂用量减少,可以减少精炼炉烟气中的可燃成分,从而减小二次燃烧系统。还原剂的加入和混合改进后,会使熔体温度更加均匀,不容易形成结块并降低耐火材料损耗。本研究中铜精炼炉采用重油喷嘴。用实际生产中的炉子尺寸和操作参数来建立流场模拟模型。主要涉及的参数有喷嘴数量、还原剂喷入速度、透气砖数量、氮气透气量。另外,还原过程中的精炼介质也要被着重考虑。文中给出了可改善还原剂的混合效果及增加还原剂停留时间的优化措施。这些措施不仅可以提高还原剂的利用率,减少还原剂的用量,还能缩短整个精炼流程时间,进而可以直接有效地提高生产效率。最后还阐述了由减少还原剂用量和提高生产效率而带来的成本节约和二氧化碳减排。

This paper considers the optimization of a plant with a numerical flow simulation, using a copper-refining furnace as an example. The goal of this optimization is to improve the conversion rate of the reducing agent. To achieve this, the way the reducing agent is added and the mixing of the melt must be improved. Both measures will lead to a reduction in reducing agent use. A smaller input of reducing agent also lowers the combustible content in the off-gas behind the re-fining furnaces. In turn this means a smaller aflerburning system. The improved input/mixing causes the temperature of the melt to be more uniform which leads to less caking in the furnace itself and therefore less wear of the fireproof material. The starting point for the optimization is a copper refining furnace with an injecting nozzle for heavy oil. The existing furnace geometry and the present operating mode make up the actual condi-tion. This actual condition is investigated in the first stage using the numerical flow simulation. This actual flow analysis is followed by flow optimization. The major parameters involved are the number of nozzles, the injection speed of the reducing agent into the melt, the number of nitrogen purging plugs, and the nitrogen purging quantity. In addition, the significance of the refining medium on the reduction process will be considered. It will be shown that optimization of the process parameters improves mixing, and the retention time of the reducing agent can be increased significantly, causing an increase in the reducing agent conversion rate.