超临界机组P91高温部件安全评估计算模型及程序开发

发布时间：2018-11-05 17:14

【摘要】：在经济快速发展的今天,人类社会对能源的需求大幅度增长,并随之造成大量污染。因此,在提高能源利用效率的同时如何能够做到减少有害气体排放成为经济发展中的一个重要课题。现代发电行业通过提高蒸汽温度和压力来实现高效、节能、环保发电,即已被广泛使用的超(超)临界燃煤技术。但这对运行设备和相应的结构完整性评估方法提出了更高的要求。大型构件在加工及焊接过程中,经常存在裂纹、气孔、夹渣、未焊透等各种缺陷,严重威胁管道的寿命。因此,高温构件中在服役过程中存在安全隐患。本文基于高温结构完整性评定技术,编制超临界机组P91钢关键高温部件缺陷寿命评估系统,实现对超临界机组主蒸汽管道、再热热段管道和集箱的高温安全评估,以保证其安全运行。通过大范围查询国内外文献、报告、会议和试验测试等手段,获得P91钢的高温拉伸性能、蠕变性能、蠕变裂纹扩展数据等;通过计算整个管系的受力状态,采用三维有限元方法计算关键部位的应力状态,包括主蒸汽管道、再热热段管道中典型的焊接接头,三通,弯头以及集箱中的后屏出口、末过进/出口、末再出口等部位。基于高温断裂力学理论,分别建立蠕变裂纹起裂和扩展两个阶段的蠕变裂纹扩展行为预测方法,起裂阶段通过裂纹孕育期的大小建立与寿命的联系,扩展阶段通过预测扩展速率建立与寿命的关系,建立高温下蠕变裂纹扩展速率预测计算模型。编制基于asp.net技术的评估网页,包括材料性能模块、应力模块、评估模块等,材料性能模块内部嵌入P91及焊接接头的各种高温性能数据,应力模块嵌入有限元计算所得的评估对象应力状态数据,评估模块将蠕变裂纹起裂和扩展评定程序化,最终形成超临界机组P91钢关键高温部件缺陷寿命评估系统。
[Abstract]:With the rapid development of economy, the demand for energy in human society has increased by a large margin, resulting in a great deal of pollution. Therefore, how to reduce harmful gas emissions while improving energy efficiency has become an important issue in economic development. Modern power generation industry achieves high efficiency, energy saving and environmental protection by raising steam temperature and pressure, that is, supercritical coal burning technology, which has been widely used. However, it puts forward higher requirements for the running equipment and the corresponding structural integrity evaluation method. In the process of machining and welding of large components, there are many defects such as cracks, pores, slag inclusions, incomplete welding, etc, which seriously threaten the life of pipes. Therefore, there are hidden dangers in the service of high temperature components. Based on the technology of structural integrity assessment at high temperature, a defect life evaluation system for the key high temperature parts of P91 steel of supercritical unit is developed in this paper, which realizes the high temperature safety assessment of the main steam pipe, the hot section pipe and the header of the supercritical unit. To ensure its safe operation. The high temperature tensile properties and creep crack growth data of P91 steel were obtained by consulting domestic and foreign literatures, reports, meetings and tests. By calculating the stress state of the whole pipe system, three dimensional finite element method is used to calculate the stress state of the key parts, including the main steam pipeline, the typical welded joints in the hot section pipeline, the three-way connection, the elbow and the rear screen outlet in the header. The end of the import / export, the end of re-exit and other parts. Based on the theory of high temperature fracture mechanics, the prediction methods of creep crack propagation behavior in the two stages of creep crack initiation and propagation are established, respectively. The relationship between the initiation stage and the life of the creep crack is established by the size of the incubation period of the crack. The prediction model of creep crack growth rate at high temperature is established by predicting the relationship between the propagation rate and the life of the creep crack. An evaluation web page based on asp.net technology was developed, including material performance module, stress module, evaluation module, and various high temperature performance data embedded in material performance module P91 and welded joint. The stress module embed the stress state data of the evaluation object calculated by the finite element method, and the evaluation module programmed the creep crack initiation and propagation, and finally formed the defect life evaluation system of the key high temperature parts of P91 steel of supercritical unit.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TG142.1;TM621

【参考文献】