Abstract: In one plant, the piping attached to the equipment was continuously vibrated during the operation of the plant and the local tip of its bracket was welded to vessel shell directly. After long-term operation, cracks occurred in the shell of the equipment from the stress concentration at the bracket tip, which led to leakage after the expansion of the cracks. This paper introduces the entire process of discovering medium leakage, identifying the leakage location, qualitatively analysing the causes, and repairing the shell cracks. The structural causes of the cracks were found through precise analysis of the stress distribution by using the finite element method. The paper also summarizes the relevant design and operation points, which can provide reference for the equipment with similar problems.

Key words: engineering cases, pressure vessel, pipeline vibration, stress concentration, leakage, crack