【作者】 刘光霞；

【导师】 王世峰；

【作者基本信息】 山东轻工业学院 ， 材料学， 2008， 硕士

【摘要】 隧道窑是无机非金属材料生产过程中应用广泛的烧成设备,一般由预热段、烧成段、冷却段三段组成。烧成段的窑体结构、燃烧设置与燃烧工艺参数决定了全窑温度制度与气氛制度实现的难易程度、烧成段温度分布均匀性及离窑烟气中NOx含量。如果烧成段结构设置与运行参数不合理,将延长制品烧成周期,降低制品烧成质量,减小能源利用率,加重环境污染,严重影响企业的经济效益与社会效益。借助计算机模拟隧道窑,对烧成段的窑体结构、燃烧设置与燃烧工艺参数进行优化,可改善窑炉运行质量,为隧道窑设计计算及运行控制提供理论基础。本文利用流体力学通用软件(CFD),根据某企业隧道窑烧成段实际结构,建立了用于数值计算的几何模型,并用混合网格(结构化与非结构化网格相结合)对几何模型进行网格划分。采用标准的k-ε湍流模型和多孔介质模型,结合窑炉的实际热工测量数据,在窑体结构、燃烧设置与燃烧工艺参数等条件作某些变化时,对烧成段温度场与NOx浓度场进行三维数值模拟,研究燃烧设置与燃烧工艺参数对窑内温度分布和烟气中NOx排放量的影响规律。模拟实验结果表明:(1)在燃料消耗量相同的条件下,空气过剩系数增大,燃料燃烧温度降低,窑内温度降低,温度均匀性增加。(2)空气过剩系数对NO排放量影响显著。在其它燃料燃烧条件不变时,NO排放量先随空气过剩系数的增大而增大,再随空气过剩系数的增大而减小,在1.1附近,NO浓度达最大值。(3)在燃料燃烧参数相同的条件下,喷嘴相错布置,窑内温度较高,温度均匀性较好,NO浓度较高。喷嘴相对布置时,窑内温度较低,温度均匀性较差,NO浓度较低。更多还原

【Abstract】 Tunnel kiln is expensively applied in the process of making inorganic non-metal materials. It often consists of preheating zone, burning zone and cooling zone. The structure, burning setup and arts parameters decide how to acquire the profitable temperature system and atmosphere system. At the same time, they also affect the temperature uniformity and NOx outputs out of tunnel kiln. If the structure setups and function parameters are irrational, there will lead to the following results: prolonging the burning period, reducing the quality of the products, reducing the utilization of energy sources, sharpening environment pollutions and affecting the economy benefits and social benefits seriously.By the numerical simulation of tunnel kiln, we can optimize the structure of tunnel kiln, burning setup and burning arts and crafts parameters, which provide the theoretic foundation for designing the kiln and controlling them.We set up the models and mesh the models with Tet/Hybrid grids.according to the real structure of the tunnel kiln. By using the computer numerical simulation and the standard k-εmodel of a CFD software, we simulate the distribution of temperature uniformity and NOx output on the different conditions. We analyse how the changes of burning setups and arts parameters affect the temperature uniformity and NOx output.The results show that:(1)As the excess air coefficient augments, the temperature reduces and the temperature uniformity improves on the conditions of the same parameters. (2)The excess air coefficients have a notable effect on NO outputs. The NO outputs are relative to the concentration and temperature of oxygen. When the excess air coefficient is 1.1, the output of NO reaches the maximum; (3) When the nozzle is in the position lack of symmetry, the temperature uniformity is good and the NO outputs is high too. On the contray, when the nozzle is in the symmetry position, the temperature uniformity is bad and the NO outputs are low too.更多还原