石油储备基地储油罐腐蚀的激光超声检测
Laser ultrasonic corrosion detection of oil tank in petroleum reserve base
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摘要: 为解决储油罐腐蚀造成的石油泄漏问题,提出基于激光超声技术的石油储备基地储油罐腐蚀无损检测方法。激光超声扫描储油罐时具有的热弹效应以及热蚀效应会生成Lamb波,利用Lamb波在储油罐中传播时对称模态和反对称模态的变化情况可对其腐蚀情况进行检测。首先通过激光扫描储油罐,利用传感器采集超声波信号,设定正常储罐罐壁的Lamb波信号为标准信号;然后根据信号的时域特征提取腐蚀散射信号,以确定储油罐是否存在腐蚀损伤,并引入腐蚀损伤因子对罐体的腐蚀深度进行预测。试验结果表明,利用激光对被腐蚀的储油罐罐体进行扫描,未被腐蚀位置处的信号强度较大,越接近腐蚀中心的扫描位置处的信号强度越弱;该方法可通过腐蚀损伤因子数值大小判断罐体腐蚀深度,为罐体更换时间提供了参考。Abstract: To solve the problem of oil leakage caused by corrosion in oil storage tanks, a non-destructive testing method for corrosion of oil storage tanks in oil reserve bases based on laser ultrasound technology was proposed. The thermal elastic effect and thermal corrosion effect generated by laser ultrasonic scanning of oil storage tanks generated Lamb waves, based on the changes in symmetric and antisymmetric modes when Lamb waves propagated in oil storage tanks. According to the structure of the oil tank, sensors were arranged to scan the storage tank with a laser, collected ultrasonic signals using the sensors, and set the Lamb wave signal on the normal tank wall as the standard signal. The corrosion scattering signals were extracted based on the time-domain characteristics of the signal. The presence of corrosion damage in the oil storage tank was determined and a corrosion damage factor was introduced to estimate the corrosion depth of the tank body. The experimental results showed that when using laser to scan the corroded oil storage tank model, the signal intensity was higher in non corroded positions, and the signal intensity was weaker as the scanning position is closer to the corrosion center; This method can determine the corrosion depth of the tank body by the numerical value of the corrosion damage factor, and provide reference opinions for the replacement time of the tank body.