Suppression of Coke Formation during Bitumen Pyrolysis
Bibliographic record
Abstract
Abstract Mild pyrolysis (400 °C) of bitumen was investigated to establish ways in which coke formation can be suppressed. Bitumen was diluted to various degrees with solvents that had different hydrogen transfer properties, namely, hydrogen donation, hydrogen shuttling, and poor hydrogen transfer properties. Additionally, the concentration of light products generated during bitumen pyrolysis was manipulated by pressure and batch/semibatch operation. Coke formation was suppressed by light material, whether added as a solvent or generated in situ during pyrolysis. As anticipated, hydrogen transfer was important, but coke formation was reduced by 35% at 10% concentration of even a poor hydrogen transfer solvent. Hydrogen availability and the H:C ratio of the reaction mixture were found to be particularly influential in determining whether coke formed. The results showed that light gases produced during pyrolysis were not irreversible reaction products, but continued to participate in the reaction network to moderate the pyrolysis process and suppress coke formation. Applied to industrial operation, evidence was provided to indicate that liquid yield can be increased and coke formation can be suppressed during visbreaking by cofeeding light gases, typically C4 and lighter hydrocarbons.
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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 | 0.000 | 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) | 0.001 | 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".