Magnetic flux leakage testing of corrosion in a 5000 m3 paraffin oil tank bottom and its integrity evaluation

Application of magnetic flux leakage (MFL) method to the testing of corrosion in a 5 000 m3 paraffin oil tank bottom was studied. The level and position of corrosion in tank bottom were obtained. It was proved by comparative the result of MFL testing, ultrasonic thickness testing and cutting plate testing that MFL inspection was reliable. According to the above thickness results and visual testing, the main reasons for the corrosion failure of tank bottom were analyzed. This paraffin oil tank bottom was integrity evaluated after repairing based on API 653 code. It was found that the paraffin oil tank bottom could be safe operation in the next periodic time (5 years).