What Fraction of the Asphaltenes Stabilizes Water-in-Bitumen Emulsions?
Bibliographic record
Abstract
It is hypothesized that only a fraction of the asphaltenes acts to stabilize emulsions and that this fraction consists of the most self-associated (least soluble) asphaltenes. To test the hypothesis, the effects of removing the least soluble versus the most interfacially adsorbed asphaltenes on emulsion stability, film properties, and mass surface coverage were compared. The least soluble asphaltenes were removed by precipitation from solutions of asphaltenes in heptane and toluene. The most adsorbed asphaltenes were removed by separating an asphaltene-stabilized emulsion from its continuous phase. Brine-in-oil emulsions were prepared using organic phases of 10 g/L of the residual asphaltene fractions from the supernatant or continuous phase. The stability of the emulsions was assessed in terms of percentage of water resolved after repeated treatment cycles involving heating at 60 °C and centrifugation at 3500 rpm. The three asphaltenes examined were extracted from a mined oil sand bitumen, a bitumen from a cyclic steam process, and a bitumen from a SAGD process. Only some of the species in the asphaltenes were found to strongly stabilize emulsion, and the size of this fraction ranged from 2% to >65% in the three samples of this study. The most adsorbed, highly stabilizing material tended to be concentrated in the least soluble fraction of the asphaltenes, consistent with the proposed hypothesis. The emulsion stability data were generally consistent with a previously observed threshold of 5 mg/m 2 asphaltene surface coverage for stable emulsions. Fractionating the asphaltenes eventually removed enough of the self-associated material that the surface coverage dropped below the threshold and unstable emulsions were observed.
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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) | 0.001 | 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 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".