During a refinery’s operation, it is a common maintenance task to periodically check tanks and other equipment for deformations, in comparison to their theoretical geometry. Significant deformations are a sign of tank wall weakening and pose a risk of critical damage, thus repairing measures have to be consider.
A cylindrical and a spherical tank at HELPE SA Aspropyrgos refinery were checked for deformations using 3D laser scanning methodology. The cylindrical tank was empty and was scanned internally from a single position, while the spherical one was operational and was scanned externally from 3 positions. After basic processing and alignment of scans, the final pointclouds were used for tank wall inspection. In particular, a cylinder and a sphere where best fitted to the respective pointclouds and deviations from those ideal primitive geometries where calculated. Results were presented in 3D, as well as in 2D sections properly spaced, in order to facilitate locating and quantifying the deformations.
3D laser scanning is an ideal methodology for this kind of maintenance inspections of industrial facilities’ equipment due to fast data capture, non-contact measurement, high accuracy and, most important, complete 3D coverage of the scanned objects. Thus, the whole object is efficiently being checked, while specialized software makes inspection tasks quite easy to perform and their results comprehensively presentable.