NST分解炉风煤料配合情况的数值模拟研究  

Numerical simulation study on air-coal mix in NST calciner

作　　者：龙泉名 赵青林[1] 姜洪舟[1] 周尚群 Long Quanming;Zhao Qinglin;Jiang Hongzhou;Zhou Shangqun(School of Materials Science and Engineering,Wuhan University of Technology,Wuhan 430070,Hubei,China)

机构地区：[1]武汉理工大学材料科学与工程学院,湖北武汉430070

出　　处：《新世纪水泥导报》2022年第1期17-22,I0013,共7页Cement guide for new epoch

基　　金：武汉理工大学材料科学与工程学院创新创业训练计划项目(项目编号:CY202036)。

摘　　要：根据某公司4000 t/d水泥熟料生产线热工参数测定结果,运用计算流体力学(CFD)数值模拟对其NST分解炉内气流场、煤粉/气流两相流场及其燃烧状态进行分析。其中,对连续相、颗粒相的计算分别采用k-ε双方程湍流模型和离散相模型;对离散相与湍流之间的相互作用采用随机跟踪模型。燃烧计算则采用有限速率/涡耗散模型。模拟结果表明,该分解炉风、煤、料的配合情况不佳,气固两相不能够高效换热,分解炉内温度分布不均匀导致入窑生料表观分解率较低。煤粉分散不均,随烟气从边侧快速离开分解炉的煤粉停留时间短,在鹅颈管内会产生滞后燃烧现象,加之K^(+)、Na^(+)、S^(4+)、Cl^(-)等离子不能够在分解炉内被及时地完全释放出来,循环富集的部分加大了预热预分解系统结皮堵塞和回转窑内结球的概率,进而影响分解炉的正常运行,这也是局部耐火衬料更换频繁的原因。建议利用本CFD模拟结果开展相应的技术改造以稳定工况,避免不必要的能量损失。According to the measurement results of thermal parameters of a company's 4000 t/d cement clinker production line,computational fluid dynamics(CFD)numerical simulation was used to analyze the airflow field,pulverized coal/airflow two-phase flow field and combustion state in its NST calciner.Among them,the k-8 double equation turbulence model and the discrete phase model are used for the calculation of the continuous phase and the particle phase respectively;the stochastic tracking model is used for the interaction between the discrete phase and the turbulent flow.Combustion calculation is based on finite rate/eddy dissipation model.The simulation results show that the coordination of air,coal and material in the decomposition furnace is not good,and the gas-solid two phases cannot effectively heat transfer.The uneven temperature distribution in the decomposition furnace leads to the low apparent decomposition rate of raw material into the kiln.Due to the uneven dispersion of pulverized coal,the residence time of pulverized coal that leaves the decomposition furnace quickly from the side of flue gas is short,and the delayed combustion phenomenon will occur in the gooseneck tube.In addition,K^(+),Na^(+),S^(4+) and Cl^(-) cannot be completely released in time in the decomposition furnace.The circulating enrichment part increases the probability of crust blockage in the preheating pre-decomposition system and the agglomeration in the rotary kiln,thus affecting the normal operation of the decomposition furnace,which is also the reason for the frequent replacement of local refractory lining.It is recommended to use the CFD simulation results to carry out the corresponding technical transformation to stabilize the working condition and avoid unnecessary energy loss.

关 键 词：数值模拟 CFD 分解炉 流场 换热 

分 类 号：TQ172.625[化学工程—水泥工业]