Leak detection is one of the main tasks of pipeline inspection, as the extension of pipelines usually requires a pipeline repair capability. Reliable and fast detection of fluid leaks in pipelines is extremely important for seaports, where their branched system is located. The most frequent locations of pipeline leakages are seam weldings and flanged joints, which are most exposed to plastic deformation. The aim of this study was to detect leaks in a technological pipeline connecting two vertical bitumen storage tanks. Based on the spectral analysis of acoustic emission signals (AE), a characteristic picture of the pipeline micro-damage process course (leakage, delamination, cracking, rupture, etc.) was obtained.