New Learnings and Trends on Duplex Stainless Steel 2205 Reactor Effluent Air Coolers
Bibliographic record
Abstract
Abstract The reactor effluent air cooler system includes the equipment and piping subject to ammonium salting, NH4HS corrosion, and associated fouling. The system typically includes air coolers. Duplex stainless steel (DSS) is one material choice to fabricate the reactor effluent air cooler (REAC) of hydrotreater units. Unfortunately, several failures from around the world have been reported in REAC units constructed of DSS, some within five years of service and others just during initial startup. Based on failure analysis reports, the failures were generally associated with welded joints. Given the condition of hydrogen-rich environment, high-pressure process fluid, and service temperature, this type of cracking is most likely a form of hydrogen assisted cracking (HAC) i.e., in-service sulfide stress cracking (SSC) at weldments or hydrogen environment assisted cracking (HEAC) occurring during tightness testing in high-pressure hydrogen. The failures are highly influenced by phase balance (ferrite/austenite) after welding, with high levels of ferrite in the weld metal or HAZ increasing the susceptibility to cracking. In this paper, a summary of considerations to weight in the design, material selection, operations and inspection approach are proposed. Focus is on material selection, inspection access, hydrogen embrittlement, full penetration welds and operation scenarios. The paper also refers to recently published technical report API 932-C. This technical report covers results of a survey of the petroleum refining industry concerning the use of duplex stainless steel (DSS) in Hydroprocessing reactor effluent air cooler (REAC) systems.
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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 | 0.002 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 0.002 |
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".