【作者】 包金哲；

【导师】 偶国富；

【作者基本信息】 浙江理工大学 ， 流体机械及工程， 2010， 硕士

【摘要】 随着国际能源日趋紧缺,煤化工行业在国内迅速发展,含固多相流对设备及管道的磨蚀易引发恶性事故,始终困扰着企业的安全生产。由于磨蚀机理复杂、相关设备及管道的运行工况恶劣,很难准确把握具体的失效位置。工程上多采用提升材质、加厚管壁等方法来预防磨蚀穿孔,大大提高了生产成本,但效果并不明显,磨蚀失效仍未得到有效控制。本文针对煤制油加氢反应器至高温高压分离器管道系统的典型气液固多相流磨蚀案例,研究腐蚀与磨损耦合作用机理;在此基础上,对多相流管道系统进行几何建模和流动磨损数理建模,采用湍流模型、多相流模型和离散相模型并求解多相流场,得到液相及固体颗粒在管道内的分布情况及管道壁面的相对磨损速率,并确定整个管道系统减薄泄漏的危险区域;通过对比分析不同管道结构和固体颗粒特性,探讨各因素对管道冲蚀磨损的影响规律,结果表明在其它条件不变的情况下,管道的磨损速率随着内径的增加而减小、管道的最佳曲率半径需要根据实际情况进行确定、固体颗粒越接近球形磨损越小、颗粒粒径越大磨损越大,但当粒径大到一定程度后,磨损速率随颗粒粒径的变化不明显;对原有管道系统进行了结构优化设计和计算分析,使新结构的磨损速率降低了近60%,优化效果明显。根据本文的磨蚀预测方法对现役管道系统进行检验布点,可明显减少在役检验工作量,并确保整个管道系统的安全。本论文的创新在于:以煤制油工艺中典型气液固多相流管道系统为研究对象,从研究腐蚀与磨损耦合作用机理出发,综合考虑液相相分率和固体颗粒磨损两个因素,采用流体动力学方法来预测磨蚀失效问题;采用单条件改变法,获得了管道的流动磨损影响规律;将预测结果及磨损规律应用于管道的结构优化和在役检验布点方案,为深入研究煤液化设备及管道的安全、稳定、长周期运行奠定了良好的理论基础。在进一步深化研究的基础上,本论文的研究成果有望推广应用于以煤化工等为代表的化工企业含固多相流设备及管道系统的磨蚀失效分析、结构优化设计、局部强化处理、在役检测定位、寿命预测、风险评估等安全保障工程,经济效益和社会效益显著。更多还原

【Abstract】 With the increasing shortage of international energy, the coal industry is developing rapidly in China. The erosion of equipment and pipe caused by multiphase flow containing solid particles has long been a security risk for enterprises. As the erosion mechanism is very complex and the operating conditions of related equipments and pipes are terrible, it is difficult to forecast the specific failure location. The regular practice in engineering is to upgrade materials and to thicken the wall to prevent erosion perforation, which increase the cost of production greatly with no obvious effect.In this thesis, the typical gas-liquid-solid multiphase flow pipeline that connects the hydrogenation reactor and high temperature and pressure separator of coal-to-liquid is the erosion case. The interaction of corrosion and wear is analyzed firstly. Then, the geometric and mathematical simulation model of the multiphase flow pipeline system is built. Turbulence model, multiphase flow model and the discrete phase model are adopted to solve the multiphase flow field. The distribution of liquid and solid particles in pipes, relative wear rate of pipe wall and the danger zone of entire pipeline system are obtained. Through comparative analysis of different pipe structures and characteristics of solid particles, the different influence factors on the pipeline wear are discussed. The results show that pipeline wear rate decreases with the increasing in diameter in the case of other conditions unchanged. The optimal pipe radius of curvature should be determined according to the actual situation. Spherical solid particles closer to the less wear, and the larger particle size the greater wear rate, until the diameter is large enough, the wear rate increases with the particle size does not change significantly. The piping system is designed and the related analysis and calculation is done. The results show that the wear rate of the new structure is sixty percent of the original. To determine the detection points of the active pipeline system with the erosion prediction method above can significantly reduce the workload of in-service inspection and to ensure the security of the entire pipeline system.The innovation of this thesis is to take the pipeline of coal-to-liquid as a typical gas-liquid-solid multiphase flow to study the interaction of corrosion and wear, to analysis liquid phase fraction and the solid particles wear synthetically and predict erosion failures using Computational Fluid Dynamics Method. The law of the pipeline wear is obtained just changing one single condition. The predicted results and the law of wear, which is applied to the optimization of the pipeline structure and in-service inspection lay a good theoretical basis for the in-depth study of coal liquefaction equipment and pipeline security, stability and long-period operation. This study provides a set of corrosion-wear failure prediction, in-service inspection and structural optimization technology. On the basis of further research, the method is expected to be applied to the abrasion failure analysis, structural optimization, local enhanced processing, in-service detection, life-span prediction, risk assessment and other security engineering of multiphase flow equipment and piping systems in coal chemical industry. The economic and social benefits must be remarkable.更多还原