Modern Inspection Methodologies for RBI Programs of Atmospheric Storage Tanks

摘要

The floor is the most vulnerable to damage part of an atmospheric storage tank. At the same time, it is the most difficult part to inspect. In fact, on-line quantitative inspection and evaluation is not possible for most tanks. On the other hand, removal of such tanks from service is a major hassle for the facility due to the downtime itself and the costs involved in emptying the product, cleaning, and assessing repairs, if any. In this respect, RBI inspection plans provide tank owners the necessary data, as to when will be the right time to remove each tank from service as well as to prioritize maintenance. Acoustic Emission - TankPac technology allows qualitative assessment of the floor condition while the tank is in-service and provides valuable input to an RBI program concerning the floor probability of failure due to corrosion. Valves attached on the tank are also evaluated for leakages, as part of the inspection. Once the tank is opened, quantitative damage assessment for maintenance actions is achieved by other advanced NDT technologies such as Magnetic Flux Leakage (MFL) mapping, Automated Ultrasonic corrosion mapping (LSI), and other methods, in accordance with pertinent codes and standards. The present paper discusses the above-mentioned technologies as part of an integrated tank inspection scheme.