分解炉技改前后性能差异的数值模拟研究

Numerical Simulation on the Performance of Precalciner Before and After its Technical Modification

基于某水泥厂实际工况,对技改前后两种不同结构的分解炉进行数值模拟。对气相采用Realizable k-ε模型,对颗粒相采用离散相(Discrete Phase Model)模型,对于煤粉燃烧及生料分解过程,采用组分输运模型(Species Transport Model)并结合有限速率/涡耗散模型(Finite-Rate/Eddy-Dissipation)进行模拟。模拟结果表明:技改前,一支主煤管与三次风管的位置不匹配,煤粉流过于集中,形成了局部高温区,且煤粉与生料耦合情况不佳,分解率不够高,为84.25%;技改后,分解炉各部分结构的改变使气流停留时间延长了,煤粉分散性更好,避免了局部高温,且煤粉与生料耦合程度高,分解率提高至95.4%,技改效果良好。

Based on the real conditions of a cement plant,numerical simulations were conducted on two different structures of before and after technical improvement precalciners.The Realizable k-c model was used for the gasphase,the Discrete Phase Model(DPM)for the particle phase,and the Species Transport Model was combined with the Finite-Rate/Eddy-Dissipation model for simulating the pulverized coalcombustion and raw meal decomposition processes.Thesimulation results indicated that before the technicalimprovement,the position of one main coal pipe was notmatched with the tertiary air pipe,causing the pulverized coalflow to be overly concentrated,forming local high-temperaturezones.Additionally,the coupling between the pulverized coaland raw meal was poor,resulting in a decomposition rate ofonly 84.25%.After the technical improvement,changes in thestructure of the precalciner extended the residence time of thegas flow,improved the dispersion of the pulverized coal,avoided local high temperatures,and increased the couplingdegree between the pulverized coal and raw meal.Thedecomposition rate was raised to 95.4%,indicating that thetechnical improvement waseffective.