Detailed Characterization of Virgin Heavy Oil Resid and Its Thermally Cracked Resid
Bibliographic record
Abstract
The vacuum resid of a Canadian bitumen and the resid of its severely cracked product were separated into 16 and 11 fractions, respectively, by supercritical fluid extraction and fractionation with pentane, followed by a comprehensive analysis of the chemical and physical properties of the resulting fractions. Thus, the effect of thermal conversion could be analyzed in detail. Characterization of the fractions included elemental analysis, density and viscosity/temperature relationship, Conradson carbon residue (CCR), molecular weight and distribution by gel permeation chromatography (GPC), boiling point curves by simulated gas chromatography (GC) up to 750 °C, saturates, aromatics, resins, and C 7 asphaltenes (SARA), C 5 asphaltenes, and proton nuclear magnetic resonance ( 1 H NMR). Moreover, the solubility parameters of selected fractions were determined from the phase equilibria of the oil fraction, propane or isobutane mixtures in a high-pressure PVT cell. The solubility parameter distribution of the C 5 asphaltenes was obtained by mixing the asphaltenes with different pentane/toluene blends. The results provide new insights into the detailed mechanism of thermal conversion. Interestingly, the heaviest fractions exhibit a larger compositional change than the lighter fractions. The asphaltene fraction is most affected, which is tentatively ascribed to the presence of multi-core compounds in this end product. The decrease in asphaltene stability is mainly caused by the asphaltenes becoming more insoluble: the change in the solubility parameter distribution of the asphaltenes is larger than a concomitant increase in the solubility parameters of the lighter fractions. The combined analytical data were used to generate typical molecular models for each of the fractions. The observed trends clearly show that the so-called Boduszynski continuum, which has been postulated for virgin crude oils and residua, is also valid for thermally cracked streams.
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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 | 0.001 | 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".