Analyses, Mitigations and Reflections From Hydrogen Stress Cracking Failure of a Duplex Stainless Steel Reactor Effluent Air Cooler (REAC) in Hydrocracker Service
Bibliographic record
Abstract
Abstract During start up following an outage for a major turnaround, a Duplex Stainless Steel Reactor Effluent Air Cooler (DSS REAC) leaked. The REAC was in a hot high pressure separation circuit of a refinery hydrocracker unit. Following the leak, detailed failure investigation was completed that revealed that the leak had occurred because of hydrogen stress cracking of the REAC tube-tubesheet welds. While the susceptibility of DSS REAC welds to hydrogen stress cracking in the form of sulphide stress corrosion cracking has been previously attributed to specific features from manufacturing, for example, ferrite-austenite phase imbalance and high hardness, over the past few years there is a growing body of evidence of the REAC DSS material experiencing cracking due to hydrogen embrittlement damage. This is despite having recommended controls in place during the original manufacturing stages. This paper will discuss the case history of the leak on the DSS REAC, including the details of failure analyses and engineering evaluation conducted on the cooler. This paper will also discuss some of the mitigations that were put in place, as well as provide reflections on the mode and mechanism of the damage.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".