Partial Upgrading of Bitumen by Thermal Conversion at 150–300 °C
Bibliographic record
Abstract
Bitumen produced from oilsands deposits has a high viscosity, which presents a challenge to pipeline transport. Ways to reduce the viscosity at low incremental production cost are desirable. Thermal conversion of oilsands-derived bitumen at temperatures in the range of 150–300 °C was explored as a potential strategy for viscosity reduction. Viscosity increased compared to the bitumen feed following thermal treatment of bitumen at 150 and 200 °C but decreased following thermal treatment at 250 and 300 °C. At all temperatures studied, changes in the chemical and physical nature of the product were observed within 1 h of reaction time, and changes continued as reaction time was extended to a period of 8 h. Hydrogen transfer and methyl transfer were important reactions. These transfer reactions appeared to be concerted in nature and did not involve cracking to release free hydrogen or methyl radicals. In fact, thermal cracking was a minor reaction. The olefin content of the liquid was low, there was little gas-make, and the H 2 S concentration in the gaseous product was low. The n -pentane insoluble (asphaltenes) content of the liquid, with a few exceptions, increased during thermal conversion, but it was poorly correlated to viscosity. It is unlikely that the change in viscosity can be attributed to a single factor. The two most important factors appeared to be (i) the formation of heavier molecules that caused an increase in “excluded volume” with a concomitant increase in viscosity and slight decrease in density and (ii) a change in the phase behavior of the product due to chemical changes in the product.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".