Safer inspection for Pressure Vessels


The non-intrusive inspection goal

Prior to the founding of The Net Zero Technology Center, the centre’s technology leadership board identified that inspection of pressure vessels was a real challenge for the industry and an opportunity for potential gain. Akselos saw this as an opportunity to work towards a net zero target and to reduce pressure vessel’s overall carbon footprint. CAN Engineering, a leader in inspection services and technology, has been part of the process to review and implement the developments made by Akselos in the industry. It has been able to gather the data and information needed to provide The Net Zero Technology Centre and the rest of the industry with insights into Akselos’ work.

The Net Zero Technology Centre is a funding organization based in Aberdeen, looking at technology in relation to challenges in the offshore energy sector. The lack of safety during inspections highlighted the need for advancements in this industry, and with the Net Zero Technology Center’s support, the issue has gained significant attention.

Demonstration of how Akselos creates its structural digital twin: From CAD model to meshing to parameterized model and to the Akselos structural digital twin.

The 3-level assessment solution

The big downturn in the industry in 2016 led Akselos to look further into the challenges associated with inspection and the associated human risk factors. They wanted to make an everlasting impact so came up with a target for 2026: To eradicate the need for individuals to go inside a pressure vessel for inspection. The projects were headed and sponsored by CAN Engineering and led to industry-changing developments by Akselos.

The projects showcased the best use case and benefits for Akeslos’ technology. In short, the technology is able to provide a complete solution that automates the inspection input data and provides a robust and accurate assessment on vessels, without the need for human entry into confined spaces.

This is made possible, in part, by the level 3 assessment that is incorporated into Akselos’ Digital Twin. The level 3 assessment consists of three checks, each of which provide data to build upon for further inspection. The first check identifies high stress components, labeled as hotspots, on which the second and third checks are conducted. The second and third checks look at the material properties of the vessel and application of the elastic-plastic model. If the solution fails to converge, the component configuration (i.e thickness) is modified and the analysis is repeated.

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Within the technology itself, there are several factors that aid in its success and accuracy. Akselos scales up and accelerates FEA (finite element analysis) using a new mathematical approach called RB-FEA (Reduced-Basis FEA). This entails component-based modeling, a two-phased approach, parametrization of components, an up-to-date condition-based model, and handling uncertainty. Using this approach, alongside the Ultrasonic Corrosion Mapping & Structural Digital Twin, Akselos has created the Pressure Vessel Digital Twin system.

Rebecca Allison, lead of the asset integrity solution sector at The Net Zero Technology Center, stated that the Pressure Vessel Digital Twin has been transformational in its ability to significantly decrease and eliminate the need for human entry into confined spaces during inspections. Even though there would be an initial investment into the system, she said that a switch to a fully NII (Non-Intrusive Inspection) program would save the industry up to 242 million pounds a year moving forward. In addition to this, it has increased accuracy via standards based data. It fundamentally calculates stress, strains and displacements which can be interpreted against any standard that is relevant to the application. It provides increased speed because it has an automated and repeatable data flow and process. With these standards in place, it has also removed the chance of errors in reporting.

The process of digital twin creation for pressure vessels can be done one time while the evaluation reporting and automation can be performed automatically.

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Fit For Service inspection workflows

Beyond the reports and data, the benefits of the Pressure Vessel Digital Twin for The Net Zero Technology Center are of immense value. Adopting this technology for future inspections would create an accurate and comprehensive system throughout the industry. It demonstrates a new workflow within the API 578 standard that is much faster than conventional workflows. It produces more accurate predictions for maintenance and inspection – including where and when repairs will be needed. It integrates high resolution inspection data and automates workflows, to enable accurate validation of the structural integrity (FFS assessment into operations). Lastly, it delivers frameworks for cost-efficient inspection and repair planning based on Digital Twin.

Due to these advantages, Akselos’ Structural Digital Twins and its industry-changing developments should become an integral part of the inspection and future planning process.