Stress and Fracture Analysis of a Fitting in Slug Catcher of Gas Refinery

This study investigates stress and fracture analysis of a small size weldolet branch in a slug catcher of a gas refinery. The CAESAR II software was used for strees analysis and investigation of the state of stress in the piping system. The analysis revealed that the high expansion stresses which exceeded the allowable stress of the ASME-B31.3 construction code resulted in the fracture of the fitting followed by plant shut down. On the other hand, auto-refrigeration due to eventual leakage from the adjacent flange led to decrease in toughness of the piping and fracture. It was shown here that by considering a flexible loop, the level of stresses due to thermal expansion would be reduced significantly which can prevent the fracture of the fitting in future. This investigation and it results found the importance of studying state of stress in low size fittings in oil and gas refining facilities.