液氨储罐腐蚀应力场有限元分析与安全评定

发布时间：2018-04-26 09:40

本文选题：储罐 + 腐蚀　；参考：《东北石油大学》2016年硕士论文

【摘要】：储罐在工作时由于受到内部介质的腐蚀,壳体壁厚会不断减薄且局部区域会出现腐蚀缺陷,这将削弱储罐的强度,严重时将对人民群众的生命财产安全以及自然环境造成很大程度上的破坏。为了研究在役储罐在受到腐蚀后的应力状态,本文根据GB150设计了一台容积为4.5m3的液氨储罐,对其建立不同腐蚀状况下液氨储罐整体和局部的有限元模型,对整体和局部结构的腐蚀应力场进行了分析与安全评定,评价了储罐的剩余强度。其中有限元分析主要分为五个部分,分别是未发生腐蚀时储罐整体结构的有限元分析和应力评定;受到均匀腐蚀的储罐整体结构的应力和位移随腐蚀厚度的变化分析和安全评定;未发生腐蚀时储罐筒体与人孔接管区的有限元分析和应力评定;受到均匀腐蚀后储罐筒体与人孔接管区的应力和位移随腐蚀厚度的变化分析和安全评定;含有两个腐蚀缺陷时储罐局部结构的应力和位移随缺陷深度变化的分析和安全评定。通过有限元分析软件ANSYS建立模型、施加工作载荷并对储罐进行结构分析,通过归纳与总结得出结论如下:不同腐蚀程度下的液氨储罐的最大应力出现在支座腹板上,同时下封头的应力分布较为复杂,储罐人孔接管结构的最大应力出现在开孔部位的接管内壁面上,通过对危险截面的线性化分析可知,受到均匀腐蚀的液氨储罐在设计使用年限能够安全运行,且人孔接管结构均满足强度要求;储罐下封头应力集中处存在的腐蚀坑对储罐强度的削弱作用随缺陷深度的增大而增大,大大缩减了储罐的使用寿命。
[Abstract]:Because the tank is corroded by internal medium, the wall thickness of the shell will be thinned and corrosion defects will appear in the local area, which will weaken the strength of the tank. When serious, it will damage the people's life and property safety and the natural environment to a great extent. In order to study the stress state of in-service storage tank after corrosion, a liquid ammonia tank with volume of 4.5m3 was designed according to GB150, and the whole and local finite element models of liquid ammonia storage tank under different corrosion conditions were established. The corrosion stress field of whole and local structures is analyzed and safety assessment is carried out, and the residual strength of storage tank is evaluated. The finite element analysis is mainly divided into five parts, which are the finite element analysis and stress assessment of the whole structure of the storage tank without corrosion. The variation of stress and displacement with corrosion thickness and the safety evaluation of the whole structure of the tank subjected to uniform corrosion are analyzed, and the finite element analysis and stress assessment of the tank tube and manhole nozzle area without corrosion occur. The variation of stress and displacement with corrosion thickness and the safety assessment of the stress and displacement of the tank tube and manhole nozzle after uniformly corroded, and the analysis and safety evaluation of the stress and displacement of the local structure of the storage tank with two corrosion defects with the depth of the defect are analyzed. The finite element analysis software ANSYS is used to establish the model, to apply the working load and to analyze the structure of the storage tank. The conclusions are as follows: the maximum stress of the liquid ammonia tank with different corrosion degree appears on the supporting web. At the same time, the stress distribution of the lower head is more complex, and the maximum stress of the manhole nozzle structure of the storage tank appears on the inner surface of the nozzle at the open hole. Through the linearization analysis of the dangerous section, it can be seen that, The uniformly corroded liquid ammonia storage tank can operate safely in design life, and the structure of manhole nozzle can meet the strength requirement. The effect of corrosion pit on the strength of the storage tank increases with the increase of the depth of the defect, which greatly reduces the service life of the tank.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TQ053.2

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