Investigation on sensor array in large vertical storage tank bottom inspection using AE methods

Dynamic defects on floor of large Aboveground Storage Tanks (AST) may lead to serious tank accidents and loss of properties. Acoustic emission (AE) has been used in storage tank floor inspection to rank maintenance priority in recent years before using other non-destructive methods, such as magnetic flux leakage, eddy current and ultrasonic. There are both economical and environmental benefits by not emptying and cleaning large storage tanks. This paper mainly covers principle of corrosion condition inspection for storage tank floor using AE method and investigation on AE sensors used in the test. Frequency, number, and installation requirements including height, space, and coupling agent are investigated in detail. Nielsen-Hsu pencil break calibration process for AE inspection channel is introduced. In the end, an AE inspection was carried out on a 20000m³ AST containing crude oil. Optimized BP Neural network is used in pattern recognition to remove electro-magnetic noise and mechanical fiction noise.