Basarab R. Prediction of residual life of intrastation technological oil pipelines by diagnosing their technical state

The most important building aspects of complex acoustic methodology for diagnostics of pipelines and oil distillation equipment state are considered in the thesis. Two-parameter methodology of the equipment residual life calculation at the fatigue crack presence is also considered. Based on long-term examination of the equipment, the physical model of factors relationship which influence the operating stations equipment material and cause fracture initiation and development is built at the thesis, as well as the model of the residual life calculation and algorithm its implementation. A methodology of the equipment state complex diagnostics by methods of acoustic emission and ultrasonic testing, that allowed revealing crack growth dynamic and its geometry are proposed. Material fracture type was found using criteria by parameters of acoustic emission signals wavelet transform. In the case of fatigue cracks identified by the developed method of diagnostics it was proposed to calculate the equipment residual life, taking into account the fatigue crack growth kinetics and hydrogen concentration at its tip. It is shown that a residual life revealed 20…25 % less in the case of taking hydrogen concentration at the crack tip into account.