The Effect Stress on Cracking of Type 304 Stainless Steel Amine Exchanger Sheets in a Gas Sweetening Plant

Amine exchanger is an important equipment which used petrochemical industries especially in gas sweetening plants. This equipment set between absorption and stripper towers and plays a vital role in amine solution regeneration process. This study investigates cracking and leakage of a UNS S30400 type stainless steel plate in an amine exchanger unit. In this regard, micro and macro examinations were performed on the plate. Also amine solution and gasket material were analyzed. After primary examinations micro cracks were observed on both sides of the plate, especially in the area with the most curvature. Also Scanning Electron Microscope examinations revealed signs of interganular corrosion which were more severe under the gasket region of the plate. Based on chemical analysis of amine solution the formate anions are three times more than accepted amounts. Results showed that the main reason of cracking was intergranular corrosion accompanied by stress. High concentration of formate in amine solution, and also high level of stress under gasket region, should have encouraged the corrosion and cracking which verifird by U-bend tests.