AE method for pressure vessel diagnostics at a refinery

Kirishinefteorgsintez was the first refinery in Russia, which introduced AE methods. Due to the advantages of the AE method for increase of reliability of equipment and the desire to test more equipment units in less time, own AE group was created and hydraulic and pneumatic tests of pressure vessels are accompanied by AE testing. The localization of defective zones by the AE method has proved to be more effective than the application of traditional NDT methods. Per Russian regulations, all pneumatic tests must be accompanied by AE testing. There is a big demand for the replacement of hydraulic tests by pneumatic tests, as the refinery operates many special vessels, which cannot be pressurized by water. For interpretation, the traditional AE criteria are used: the localization of AE sources, verification of the Kaiser effect, pressure holding AE etc. AE source location with different wave velocities in the relatively thin shells (the different Lamb waves modes) and some cluster analysis algorithms are also used. 205 vessels have been tested since 1992. 29 of these vessels had been repaired due to the result of the AE testing. An AE test database has been formed and includes results of the AE testing and the corresponding follow-up inspections.