The inspection of the polymer-coated zones of the digester tanks used in a plant for sewage treatment was carried out as a predictive-preventive maintenance activity. The results obtained were analyzed according to API 650 and API 653 codes.
Large amount of sludge is accumulated in different regions of the digester tanks due to its operation which generates corrosive wear in its structure. Inspection using ultrasonic testing was made in order to determine the thickness of the plates and the sanity of the welded joints to estimate the lifetime of the digester and the corrosion rate of the structure.
The results allowed to generate the following benefits for our customer:
Optimized maintenance activities programming
Extended inspection interval
Increased reliability in the operation of the digester tanks
Identification of critical points for potential failure
Identification and evaluation of plans for mitigate wear in the structure, as well as recommendations in case of repair critical regions of the tanks
Design and implementation of a methodology for inspection that can be replicated in similar structures
