Microstructure Analysis and Fitness-for-Service Assessment of Hydrogen-Induced Cracking in an Amine Tower

In the oil and gas industries, the reliability of pressurized components is essential for ensuring safety and continuous operations. The amine tower is a critical part of gas-treating refineries, responsible for gas sweetening. This study focused on conducting a fitness-for-service assessment of an amine tower experiencing hydrogen-induced cracking. The material conditions of the damaged tower were determined by examining a retired tower fabricated from the same heat number material. The assessment was carried out following the API 579-1/ASME FFS-1 guidelines, specifically utilizing sections 7 and 9 for level 3 assessments. Section 7 involves assessing the load-bearing capacity of the vessel, while also considering the dimensions of defects in the tower's formed head to evaluate crack-like flaws using the failure assessment diagram defined in section 9. This analysis determined that the damaged tower, containing the HIC defect measuring 2480 × 2480 mm with a depth of 16.1 mm, could safely withstand an internal design pressure of 8.963 MPa, taking into account welding residual stresses. The findings indicated that the damaged area fell within the acceptable region of the failure assessment diagram, thereby confirming the continued safe operation of the HIC-damaged amine tower.