Effects of Reaction Kinetics of H2S, CO2 and O2 on the Formation of Black Powder in Sales Gas Pipelines
Bibliographic record
Abstract
Abstract Carbon dioxide (CO2), hydrogen sulphide (H2S) and oxygen (O2) gases dissolve in water condensate on carbon steel pipelines that react with the walls to form iron carbonate, iron sulphides, and iron oxides as the corrosion products, respectively. It is unknown whether these gases react individually or if there is a competition between them leading to a kinetically favorable reaction. The reaction rate is governed by the concentration of gases dissolved in water which is in turn controlled by the gas composition, diffusivity, solubility, and the intrinsic kinetics. The reaction rate and products when fine iron powder (-325 mesh) suspended in water exposed to dry acid gas (CO2 and H2S) and exposed to humid acid gas are studied. Our findings show that water immersion approach for corrosion study without mixing has a mass transfer resistance that slows down the reaction rate significantly. This may not be observed in actual gas pipelines as the pipeline is exposed to thin water film only and the turbulence created by the gas flow induces mixing. Iron sulphide and carbonate formation are found to depend on the CO2/H2S ratio and time. Initially, the formation of iron carbonate is more dominant than iron sulphide. Higher the CO2/H2S ratio leads to the higher iron carbonate formation than iron sulphide. Iron sulphide becomes more dominant in a longer time scale for all CO2/H2S ratios. Iron sulphide is oxidized to elemental sulphur when O2 is present.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".