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Comprehensive Corrosion under Insulation (CUI) Management for Cryogenic Service: A Facility-Specific Approach with Broad Industry Implications

In the realm of corrosion management, corrosion under insulation (CUI) poses significant challenges, particularly for facilities operating in cryogenic service. A comprehensive approach to understanding and mitigating CUI risks is crucial for ensuring asset integrity, safety, and operational efficiency. This paper presents an in-depth case study of a natural gas liquids (NGL) fractionation facility, demonstrating the successful implementation of a holistic CUI management strategy applicable to a broader industry context. Notably, the facility has faced unique challenges, as some circuits have not been shut down or inspected for the past 40 years. The paper details the extensive work carried out, encompassing risk mapping, mitigation strategies, inspection planning and prioritization, and repair planning. By adopting a systematic approach, the study effectively identifies and addresses CUI risks in the facility's cryogenic service operations. The results of this research contribute to the existing body of knowledge on CUI management in cryogenic service, offering a recommended path forward for the industry to tackle CUI-related issues. By showcasing a comprehensive and adaptable approach, this paper holds great potential to foster increased safety, reliability, and efficiency in the corrosion industry, paving the way for future research and collaboration.
Product Number: 51324-21071-SG
Author: Abdullah M. Alratoee; Ricardo S. Costa; Meshary A. Al-Bahli; Faisal M. Al-Mutahhar; Mohamed A. Ahmed
Publication Date: 2024
$40.00
$40.00
$40.00
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Pitfalls in the Typical RBI Methodology for CUI Management Programs

Product Number: 51324-20894-SG
Author: Ahmad Raza Khan Rana; Joel Chapman; Touqeer Sohail; Syed Umair Niaz Bukhari; Graham Brigham
Publication Date: 2024
$40.00
Modern-day risk-based inspection (RBI) platforms are designed to evaluate the safety and/or financial risk of assets using industry-recommended RBI methodologies (e.g., API 581). There are cases where the RBI methodology does not represent the true risk profile of the asset, despite implementing the best possible inspection programs and careful input of inspection data. One of the main pitfalls present is the inherent limitation in the risk calculation methodologies that makes no or little use of the inspection data. An example of such a situation is the CUI risk assessments that are subjected to uncertainties due to numerous scientific parameters that are partially addressed (or even unaddressed) in modern-day RBI approaches. This work addresses two case studies of external corrosion rates due to CUI for two pairs of test rigs made with small bore piping deployed with two different insulation designs, namely conventional design, and moisture egress design. The assemblies were tested using two different methods for CUI simulation and testing conditions. The first pair was tested per ASTM G189-07 under isothermal wet-dry conditions at 100 °C (212°F) for three days, while the second pair was submerged under water for two days followed by outdoor exposure for one year. The experimentally determined corrosion rates were compared to those calculated using API 581-compliant RBI software. The comparisons of resulting corrosion rates are complemented by an explanation of the deviations and pitfalls.