Use of <sup>13</sup>C Tracers to Determine Mass-Transfer Limitations on Thermal Cracking of Thin Films of Bitumen
Bibliographic record
Abstract
Thermal cracking of +524 °C Athabasca bitumen at temperatures greater than 500 °C with various thicknesses of feed deposited on the reactor walls was investigated to determine if mass-transfer limitations were significant in controlling product yields. A quartz tube microreactor was used for the bitumen cracking reactions. Volatile products were removed as they evolved by constant purging of the reactor with nitrogen. Coke yields decreased from 23 to 18% with decreasing initial film thickness from 150 to 15 μm. A 13 C-labeled tracer representative of reaction fragments from bitumen was synthesized and added to the feed in order measure incorporation of products into the coke via retrograde reactions. A 23% decrease in overall incorporation of the tracer was observed when the initial film thickness was reduced from 150 to 15 μm. A mechanism involving competition between mass-transfer of volatile compounds through the reacting liquid and retrograde reaction is proposed.
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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".