论文总字数：24517字

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液固两相流磨蚀案例，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，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、500mm最佳，管道的最佳曲率半径需要根据实际情况进行确定，4倍最佳。本文采用单条件改变法，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。

关键词：煤制油 气液固多相流 磨蚀机理 磨蚀预测 工程应用

Study on the erosion and corrosion of pipes under high current velocity and solid conditions

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 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，500mm is the best. The optimal pipe radius of curvature should be determined according to the actual situation，4 times is better than any other one. 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.

Keyword: Coal-to-liquid; Gas-liquid-solid multiphase flow; Erosion mechanism; Erosion forecast; Engineering application

目 录

摘要 I

ABSTRACT II

第一章 绪论 1

1.1 研究意义及背景 1

1.2 国内外研究现状及发展趋势 2

1.2.1 物料磨损机理研究 2

1.2.2 多相流理论及磨损预测研究 3

1.3 本文主要研究内容 4

1. 液固两相流管道腐蚀典型案例................................................................................5

2.1 典型案例介绍..........................................................................................................5

2.2 煤化工案列介绍......................................................................................................6

2.3 本章小结 8

第三章 流体力学理论及CFD建模 9

3.1 FLUENT介绍 9

3.2 GAMBIT网格划分 10

3.3 边界条件 12

3.4 本章小结 15

第四章 多相流管道腐蚀模拟及磨蚀分析 16

4.1 几何模型 16

4.2 运用FLUENT求解 16

4.3 模拟结果计算及分析 21

4.4 磨蚀分析................................................................................................................26

4.5 本章小结 27

1. 磨蚀影响因素及应用研究......................................................................................28

5.1 弯管结构特性影响研究........................................................................................28

5.1.1 管径的影响................................................................................................28

5.1.2 曲率半径的影响........................................................................................30

5.1.3 流速的影响................................................................................................31

5.1.4 颗粒直径的影响........................................................................................33

5.2 三通管结构............................................................................................................34

5.3 本章小结................................................................................................................36

1. 总结展望..................................................................................................................38

6.1 本文研究工作总结................................................................................................38

6.2 今后研究工作展望................................................................................................38

参考文献 40

致 谢 42

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