罐底缺陷声发射检测实验研究

发布时间：2018-12-25 13:35

【摘要】：随着石油及石油化工产品在各大工业领域的广泛应用,世界对石油的依赖程度与日俱增,地上立式金属常压储罐以便于管理、低成本以及低投入等优点,已成为石油储备基地上主要的储油容器,并且正向着集成化和大容量化发展。由于储罐材料本身及外界环境的影响,储罐坑点和裂纹等缺陷不可避免地出现,大大降低了储罐的安全性,增加了存储介质泄漏事故的发生率,进而造成环境污染和经济损失。储罐底板缺陷位置隐蔽,且事故发生率随储罐服役年数的增长而增大,因此需要对储罐底板的缺陷情况进行定期检测。常规的检测方法需要停止储罐作业,排出罐内产品并清理罐内剩余的淤积物,最后采用漏磁检测或超声波检测等方法进行罐底缺陷检测,浪费人力、物力和财力。声发射检测方法无需停产,采取“被动听声”的方式,采集罐底缺陷声发射信号,确定缺陷的位置和缺陷发出声发射信号的时间,评定缺陷的严重性。经查阅文献,目前罐底缺陷声发射检测已取得一定成绩,但是仍无法对罐底缺陷进行定性判断和定量分析。本文围绕该问题,进行室内实验研究,具体研究内容及成果如下。一、建立了室内立式金属常压储罐模型,并在罐底板上分别构造了典型尺寸的圆柱形坑点缺陷以及裂纹缺陷。二、对声发射仪进行了二次开发,配置了波形采集卡和波形分析软件包,开发了多重滤波功能,优化了滤波参数,提高了滤波去噪的效果。三、编制实验计划书,按实验计划书进行实验,采集罐底坑点和裂纹缺陷的声发射信号数据。四、联合通过多重滤波和归一化分析方法,得到了声发射特征参数与坑点、裂纹缺陷发展程度的对应关系,建立了相应的缺陷定量数学模型和缺陷声发射特征参数数据库,从而实现了对坑点和裂纹缺陷的定量分析。五、联合通过频谱分析和小波分析处理方法,得到了声发射频谱特征与坑点、裂纹缺陷的对应关系规律,从而实现了对典型缺陷的定性分析。六、采用坑点和裂纹缺陷定量数学模型,对常压储罐底板声发射现场检测采集到的数据进行分析计算,将计算结果与开罐检测的结果进行对比分析,得到坑点缺陷定量数学模型的准确率可达到76%,裂纹缺陷定量数学模型的准确率可达到75%。
[Abstract]:With the wide application of petroleum and petrochemical products in various industrial fields, the world relies more and more on petroleum. The above ground vertical metal storage tanks have the advantages of easy management, low cost and low input. It has become the main oil storage container in petroleum reserve base, and is developing towards integration and large capacity. Because of the influence of the storage material itself and the external environment, the defects such as pits and cracks inevitably appear, which greatly reduce the safety of storage tanks, increase the occurrence of leakage accidents of storage media, and then cause environmental pollution and economic losses. The defect location of tank bottom plate is hidden, and the accident rate increases with the increase of tank service years, so it is necessary to check the defect situation of tank bottom plate regularly. The conventional detection methods need to stop the tank operation, discharge the products from the tank and clean up the remaining silt in the tank. Finally, the method of magnetic flux leakage or ultrasonic detection is used to detect the defects of the tank bottom, wasting manpower, material resources and financial resources. The method of acoustic emission detection does not need to stop production. The method of "passive listening sound" is adopted to collect the acoustic emission signals from the bottom of the tank, to determine the position of the defects and the time when the defects send out the acoustic emission signals, and to evaluate the severity of the defects. After consulting the literature, some achievements have been made in acoustic emission detection of tank bottom defects, but it is still impossible to make qualitative judgment and quantitative analysis of tank bottom defects. Around this problem, this paper carries on the indoor experiment research, the concrete research content and the result are as follows. The main results are as follows: 1. The model of indoor vertical metal storage tank under atmospheric pressure is established, and the typical cylindrical pothole defect and crack defect are constructed on the bottom plate of the tank. Secondly, the acoustic emission instrument is redeveloped, the waveform acquisition card and waveform analysis software package are configured, the function of multiple filtering is developed, the filtering parameters are optimized, and the effect of filtering and de-noising is improved. Thirdly, the experiment plan is compiled, according to the experiment plan, the acoustic emission signal data of the bottom pit point and crack defect of the tank are collected. Fourthly, by combining the methods of multiple filtering and normalized analysis, the corresponding relationship between the characteristic parameters of acoustic emission and the development degree of pits and crack defects is obtained, and the corresponding quantitative mathematical model of defects and the database of characteristic parameters of acoustic emission of defects are established. Thus the quantitative analysis of crater point and crack defect is realized. Fifthly, through the combination of spectrum analysis and wavelet analysis, the corresponding relationship between acoustic emission spectrum characteristics and pits and crack defects is obtained, and the qualitative analysis of typical defects is realized. Sixthly, the quantitative mathematical model of pit point and crack defect is used to analyze and calculate the data collected from the acoustic emission detection of the bottom plate of the atmospheric storage tank. The calculated results are compared with the results of the open tank detection. The accuracy of quantitative mathematical model of pit spot defect can reach 76%, and that of crack defect model can reach 75%.
【学位授予单位】：中国石油大学(华东)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE972

【参考文献】