Experience in Monitoring Brazed Aluminium Heat Exchanger, after Major Repairs

Brazed Aluminium Heat Exchangers are fundamental for a natural gas liquid recovery plant. Refrigeration at cryogenic temperatures and the liquefaction process take advantages from their thermal hydraulic efficiency and compactness characteristics, making such units economically feasible. These exchangers are proprietary design, with only a few manufacturers around the world and limited knowledge about their maintenance. After two failures in the same equipment with possible thermal fatigue contributions, occurring only nine months apart, two complex repair procedures had to be carried out. To ensure operational safety, online monitoring through Acoustic Emission Technique has been performed. This monitoring led to discoveries of systems and routine maneuverer that triggered damage mechanisms. This allowed for the implementation of adjustments to mitigate the propagation of damage, thereby increasing the equipment's lifespan. The procedure applied in this type of equipment constitutes an innovative approach using the Acoustic Emission technique, which has resulted in a successful strategy of condition monitoring.