中央扩散式精矿喷嘴气粒混合特性数值模拟

Numerical simulation on gas-particle mixing characters of CJD burner

为解决中央扩散式精矿喷嘴生产时存在的下生料、塔体寿命缩短、氧利用率下降等问题,建立离散分散风孔型精矿喷嘴数学模型,数值模拟研究工艺风和分散风变化对喷嘴出口附近区域气粒混合流动的影响。结果表明:工艺风集中于圆环状柱体区域内流动;颗粒分散受控于分散风与工艺风动量比,动量比过小塔中心区域出现料柱、动量比过大塔近壁区域出现料环;小动量比可实现颗粒适度分散和气粒良好混合。喷嘴气粒混合仿真规律和冷模实验吻合。

To solve the non-uniform gas-particle mixing problems such as the falling raw concentrate remain, shorter reactor shaft lifetime and less oxygen utilization at the high loading flash smelting process with a CJD burner, a mathematical model of a CJD burner with distribution air was built up. The changing rule of gas-particle mixing with the momentum ratio of distribution air to process air near the nozzle was simulated. The results show that the process air is concentrated inside the circular cone under the nozzle, the particle distribution is effectively controlled by the momentum ratio. Too smaller momentum ratio leads to the particles concentrated inside the cylinder center, and too large leads to the particles near the tower wall. The small distribution air can give a suitable distribution of particles and a moderate gas-particle mixing. This numerical simulation matches cold model test very well.