【作者】 李祥东；

【导师】 叶旭初；

【作者基本信息】 南京工业大学 ， 材料科学与工程， 2003， 硕士

【摘要】 窑外分解技术是国际公认的代表当代最高技术水平的水泥生产方法，该技术的关键设备之一是分解炉。分解炉种类很多，它既是一个燃烧炉，同时也是一个化工反应装置，具有气固输送、燃料燃烧、气固换热和碳酸盐分解等多种功能。由于分解炉内燃料燃烧和生料分解这两个反应是悬浮于气流中进行的，且各过程相互制约，这就使得分解炉的研究开发工作具有很大的难度。分解炉研究手段的先进性往往决定了研究所能达到的水平。就分解炉研究的数值方法而言，国内的许多研究者已经作了大量的工作，取得了一定的成就，但离工程实际应用还有很大的差距。CFD(Computational Fluid Dynamics)技术发展到今天，已逐渐作为一种新手段而日益受到重视并得以广泛地应用和发展，已能成功地解决如气固两相流动、高温传热、煤粉燃烧等分解炉所涉及到的部分物理、化学过程。但是，分解炉有其自身的特点，煤粉和生料混合悬浮于气流中形成无焰燃烧，放热和吸热同时进行，这是其他任何行业少有的，现有的CFD通用软件不能直接应用于分解炉热工状态的数值模拟。为此，本文在已有的CFD软件的基础上，参考了AEA的部分源程序，针对分解炉内燃烧和分解的特点开发了适用于分解炉热工状态分析的数值计算软件，为CFD技术在分解炉中的应用研究提供了必要的基础。本文按照分解炉内各参量的比例关系设计了一个结构相对简单的矩形管道，并以此为研究对象进行燃烧和分解的数值计算软件的开发和调试。结果表明，管道内及管道出口温度分布均匀，并与分解炉内的温度分布规律非常接近，气相组分变化合理，进而证明了本文开发的数值计算软件的正确性及合理性。在分解炉的数值模拟研究中，煤粉和碳酸盐反应动力学参数的正确给定是非常重要的，参数的合理性直接影响到计算结果的正确性。本文采用高温反应炉分别对这两个过程的反应动力学参数进行实验研究，获得了碳酸钙以及煤粉的活化能和频率因子，为分解炉的数值模拟提供了反应动力学参数。在以上研究成果的基础上，本文以南京水泥工业设计研究院开发的喷旋管道炉为实例进行数值模拟研究，获得了流场、颗粒运动轨迹、压力场、温度场、组分浓度场、生料分解率以及煤粉燃烬率等多项参数，全面、精细、直观地反映了喷旋管道炉内的热工状态。计算结果与南京水泥设计研究院的设计参数及热工标定结果吻合良好，说明该数值模拟的理论及结果是可靠的，证明本文开发的软件有能力预测分解炉的热态工况，可用于优化分解炉的结构和指导分解炉的操作。更多还原

【Abstract】 It has been publicly acknowledged that the Technology of Precalcination is the most advanced cement manufacturing method. Precalciner, the most important machine in the System of Precalcination, is a combustion furnace and a chemical reaction equipment. Multi-phase flow, combustion of fuel, heat transfer and decomposition of carbonate co-exist in it. The main chemical reactions in a precalciner, namely the combustion of pulverized coal and the decomposition of carbonate, occur in a suspending state and interact with each other, which makes the researching jobs extremely tough. The researching methods always decide the level of researching jobs on precalciners. Native researchers have struggled a lot to study precalciners numerically, but they still have a long way to go to put their achievements into factual use.Since CFD (Computational Fluid Dynamics) Technology was invented, it has been attached great importance as a new technique and has been greatly developed. By now, it can be used to solve some problems involved in a precalciner, such as multi-phase flow, heat transfer and combustion of pulverized coal, etc. But precalciner is characterized by its own traits, for example, pulverized coal combusts without flame because of the existence of raw meal, which is a particular phenomenon that could not be found in other industries. As a result of this, the existing CFD softwares could not been directly adopted in the numeric simulation for a precalciner. In order to resolve the problem, a new method was put forward by combining a piece of routine compiled in the dissertation with the existing CFD softwares. The routine is designed to deal with the combustion of pulverized coal and the decomposition of carbonate.A long and thin cubic pipe geometrically is built to debug the routine. Parameters in the debugging are set according to those of a typical precalciner. Results of the debugging showed that the temperature in the pipe was equally distributed and the temperature on the outlet was almost equal to that of a normal precalciner. In addition, the mass fractions reasonably varied alone the pipe. Carbonate almost decomposedcompletely. All of the above means that the routine designed in the dissertation is able to describe the process of combustion and decomposition.In the particular numeric simulation for a certain precalciner, it is very important to properly set the kinetic parameters of char and carbonate, because improper parameters always lead to useless results. In order that correct parameters were given in the simulation, kinetic experiments were carried out on a high-temperature furnace and corresponding parameters were got.With the routine and parameters, we carried out a numeric simulation by taking the ejecting-revolving pipe precalciner designed by NCDRI (Nanjing Cement Design and Research Institute) as a geometric model. Parameters such as flow field, particles’ tracks, pressure field, temperature field, decomposition proportion of raw meal and combustion proportion of pulverized coal, etc. are got. The result inosculated with the reports from NCDRI, which means the routine is capable of forecasting the properties of a newly designed precalciner and is capable of providing information to improve its structure and operation.更多还原