Leveraging Recent Advancements in Fitness-For-Service Technology to Optimize Equipment Minimum Allowable Temperature / Minimum Pressurization Temperature Limits

Abstract There is often a tremendous financial incentive to reduce the time required to ramp a processing unit up to full operating capacity. However, it is imperative that equipment startup and shutdown procedures are safely established using the appropriate technical justification to minimize the potential for catastrophic consequences. The 2021 edition of API 579-1/ASME FFS-1 (API 579) Fitness-For-Service (FFS) included several significant technology enhancements to Part 9 Assessment of Crack-like Flaws. These enhancements can be employed in a fracture mechanics-based approach to optimize equipment minimum allowable temperature (MAT), or minimum pressurization temperature (MPT), limits even when the equipment may be subject to toughness degradation mechanisms such as temper embrittlement or hydrogen embrittlement due to the operating environment. This paper reviews several historical approaches to establishing hydroprocessing equipment MAT/MPT limits and provides a summary of the recent modifications to API 579 Part 9 (and its associated Annexes). The paper also provides insight into future procedural and technical updates that the ASME/API Fitness-For-Service Joint Committee (FFSJC) is considering in order to address existing deficiencies and inconsistencies in the current assessment procedures. Lastly, the paper includes four case studies demonstrating the implementation of the API 579 procedures to optimize MAT/MPT limits for various heavy wall hydroprocessing reactors.