【作者】 豆海建；

【导师】 陈作炳；

【作者基本信息】 武汉理工大学 ， 机械电子工程， 2009， 博士

【摘要】 新型干法水泥生产技术是目前国际上最先进的水泥生产技术,已达到日产万吨规模。进几年来,两档支撑短窑技术(L/D:10.5～12.5)相对于长窑技术(L/D:14～17)具有低能耗、高运转率、易操作等优势成为世界各大水泥技术集团的青睐,成快速发展势头。短窑技术的发展对预分解系统的性能指标,尤其是入窑生料的分解率,提出了更高的要求。尽管近些年来我国水泥工业取得了较大的发展,但在热耗、电耗、污染物排放等方面同国际先进水平仍存在较大的差距,如国际先进水平的单位质量熟料热耗约680kcal,我国720kcal。预分解系统是实现节能、降耗、减少污染物排放的关键系统,因此开展预分解系统热态流场的研究不仅能促进我国短窑技术的发展,增强我国水泥技术的国际竞争力,而且对实现我国水泥工业节能、降耗、清洁生产发展目标也具有重要的现实意义。本文基于预分解系统流场的国内外研究现状,同时结合赞比亚拉法基CHILANGA 2000t/d生产线的生产调试工作,首次实现了预分解系统热态流场的研究,解决了系统流场研究中必须解决若干关键问题,如旋风筒灰斗出口边界算法等,主要研究内容如下:(1)采用组分传输的方法实现了分解炉内煤粉燃烧的研究,并为此建立了基于煤的工业分析、元素分析结果研究煤挥发份化学式的方法。(2)在前人的研究成果基础上,完善和发展了分解炉内生料在悬浮态下的生料分解模型,并基于工程试验生产线的化验室条件和生料分解模型,研究得到了以“高温炉-电子天平-秒表”为主要测试仪器的生料分解动力学参数试验方法,克服了水泥生产线化验室不配备热重分析(TGA)天平的客观条件。(3)基于CFD(Computation Fluid Dynaimcs)商用软件Fluent6.3的多相流动程序结构和生料分解数值解析模型,采用多相组分传输的方法,二次开发研究得到了生料分解反应的数值求解算法及程序,实现了分解炉内煤粉燃烧-生料分解耦合流场的研究,并得到了工程试验数据的检验,取得了较好的吻合性。(4)通过深入分析旋风筒灰斗出口气固两相的实际流动过程,研究得到了旋风筒灰斗出口边界算法,并借助于Fluent多相流动的程序结构,二次开发研究得到了基于灰斗出口气固流动实际过程的旋风筒收尘效率求解算法。采用“欧拉-欧拉”方法研究了旋风筒内气固两相流动过程,首次实现了基于旋风筒灰斗出口气固流动实际过程的旋风筒收尘效率研究,并得到了试验数据的有力验证。(5)在旋风筒气固两相流动和收尘效率研究的基础上,首次研究得到了基于旋风筒内完全气固流动过程和严密热平衡理论的旋风筒换热效率研究方法,对建立预热器换热效率的研究方法奠定了重要的理论基础。(6)根据预热器系统的工艺过程,在旋风筒内气固两相流动研究的基础上,研究得到了预热器系统气固两相流场求解算法,国内外首次实现了预热器系统气固两相流场的研究,并在此基础上,研究得到了基于预热器内完全气固流动过程的预热器换热效率研究方法,该方法彻底摆脱了工程上以C1出口温度定性评估预热器换热效率的不足,也克服了预热器对环境散热的不确定性对换热效率计算的制约,不仅能定量评估同一个预热器在不同工况条件下的换热效率,而且可以定量评估不同系列、不同规格、不同型号的预热器之间的换热效率的高低。因此,该方法不仅可以指导预热器的工业生产实践,优化操作工艺参数,而且可以直接用于指导预热器的开发设计工作。(7)结合中材建设有限公司(CBMI)的拉法基永川5000t/d总包项目,采用本文的分解炉流场研究方法首先对该生产线分解炉的初始设计方案进行了数值模拟研究,并针对模拟结果中的不合理之处提供了优化改进方案;其次,基于改进方案再次进行耦合流场的数值模拟研究,取得了较为合理的流场分布,为该分解炉的设计工作提供了重要的理论指导。更多还原

【Abstract】 and research results in this dissertation are decribed as the following:(1) Species transport method is adopted to simulate the combustion process inside calciner by developing the method of deducing the molecular formula of coal volatile matters based on the proximate analysis of coal and ultimate analysis of coal.(2) Based on the previous research works all over the world, the decomposition model of raw meal particle suspained in calciner is studied and developed. The chemical kinetic parameters test method of raw meal decomposition is developed by using high temperature furnace, electronic balance and stopwatch as main test instruments according to the practical condition on the spot, overcoming the difficulty that thermal gravity analysis (TGA) blance is not equipped at production line labouratory.(3) Based on multiphase flow program hierarchy of CFD commercial software(Fluent6.3) and the numerical analytical model of raw meal decomposition, multiphase species transport method is adopted to further develop the numerical solution programe of raw meal decomposition, which realizes the coupled flow field study of coal combustion - raw meal decomposition inside calciner. A good consistency is achieved by comparing simulation data with engineering test data from production line.(4) The boundary condition algorithm of cyclone ash outlet is achieved by deep analysising the practical gas-solid flow processes happen in cyclone ash outlet and ash discharge pipe, and then the dust collection efficiency numerical solution programe is developed with the help of multiphase flow program hierarchy of Fluent. "Euler-Euler" method is adopted to simulate the gas-solid multiphase flow inside cyclone, and the study of cyclone dust collection efficiency that is based on the practical gas-solid flow processes in ash outlet is simultaneously realized for the first time, which is convincingly proved by test data.(5) On the basis of finishing the studies of cyclone gas-solid two phase flow and dust collection efficiency, the study of cyclone heat exchanging efficiency is realized that is based on the thorough multiphase flow inside cyclone and rigorous heat balance principle, which lays the important theoretical foundation for establishing the research method of preheater heat exchanging efficiency. (6) According to the technics process of preheater system, the solution algorithm of gas-solid two phase flow field inside preheater is developed, and then the study of gas-solid two phase flow field inside preheater is realized for the first time all over the world. On the basis of the study of preheater gas-solid two phase flow field, the research method of preheater heat exchanging efficiency is developed that is based on the thorough gas-solid flow process inside preheater. This kind of preheater heat exchanging efficiency research method thoroughly breaks away from the disadvantages that use C1 outlet temperature to approximately evaluate the heat exchanging efficiency of preheater in engineering, and also overcomes the restriction that is difficult to calculate the heat exchanging efficiency due to the indetermination of prheater heat loss to the outside, therefore it can not only calculate the heat exchanging efficiency of the same preheater at different woking conditions, but also can do those of preheaters with different series, size, and type. As a result, this research method of preheater heat exchanging efficiency can not only guide the industry production practice of preheater, optimizing some operation parameters, but also can be directly used to aid the preheater’s development and design work.(7) Aiming at CBMI general contract project of Larfage Yong Chuan 5000t/d production line, firstly, by using the research method of calciner flow field in this dissertation, the numerical simulation is carried out for the calciner initially designed for this production line, and then some corresponding optimization schemes are put forward for the unreasonable flow characters from the simulation results; secondly, based on the optimized shceme, the coupled flow field is simulated again for the optimized calciner and achieves more reasonable flow field distribution, which provides important theoretical guide for the design work of the calciner in this production line.更多还原