Experimental Research On On-line Acoustic Emission Testing For Atmospheric Pressure Storage Tanks Floor And Its Engineering Application

The atmospheric pressure storage tank filled in crude oil, intermediate petrochemical product, raw material and finished oil product is an important storage device. The corrosion of tank floor is one of decisive factors for its safe operation. To ensure its safety, the corrosion of tank floor needs to be testing. Although some routine testing can be done for floor of tanks opened, it is now more and more difficult for making a normal inspecting to open tanks for large scale installations linked closely. However, there are still no effective methods or techniques to test the corrosion of floor under a not opened condition, Even if storage tanks can be detected in an opened state, some locations can still not be checked for various reasons.This thesis studies mainly the relevant test techniques used for floor of tank during its operation or under its opened state. Major contents are as follows:1. Two simulated storage tanks of different sizes were used to research the related factors of influencing accuracy of locating acoustic emission source on-line.2. It is analyzed for current situation of ultrasonic guided wave technology and its basic principle. Thereafter, plenty of testing boards with different artificial defects is made in the laboratory to evaluate these emulate defects by using of ultrasonic guided wave for determining the detect-ability with regard of the influence of thickness losing and locating of defects.3. The acoustic emission on-line monitoring technique was used for a using real-case tank, the detection results of which were compared with that of ultrasonic guided wave and magnetic flux leakage technique for the tank opened to confirm further the reliability of on-line acoustic emission and guided wave technology.Finally, it is verified that on-line acoustic emission and ultrasonic guided wave detecting technology can give play to relevant effects on testing for tank floor on site, and also, the blind area of magnetic flux leakage detecting can be reduced and various defects can timely found.The method suggested in this thesis is proven in petrochemical production practice and have a good application effect, and can be used to solve the blind area problem during detecting floor of atmospheric pressure storage tank.