Effect of Solvent-to-Bitumen Ratio on the Pyrolysis Properties of Precipitated Athabasca Asphaltenes
Bibliographic record
Abstract
The first stage in the conventional hot water process for extracting bitumen from mined oil sand produces a bitumen froth containing substantial amounts of emulsified water and fine solids. Dilution of the froth with a sufficient quantity of a paraffinic solvent, such as hexane, causes the aggregation and rapid settling of water droplets, solid particles, and precipitated asphaltenes. The fraction of asphaltenes precipitated from the bitumen increases with the solvent-to-bitumen ratio ( S / B ). This paper reports the results of thermogravimetric measurements of asphaltenes precipitated from Athabasca bitumen using hexane at S / B values ranging from 1.1 to 3.5. For all samples, approximately 60 wt % of the hydrocarbons was volatilized below 525 °C, and most of the remainder was transformed into coke. Pyrolysis-gas chromatography and photoacoustic Fourier transform-infrared spectroscopy support the conclusion that varying S / B does not greatly alter the chemical composition of the precipitated asphaltenes and their pyrolytic products.
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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 | 0.001 |
| 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".