Hydrogenation of Olefins in Bitumen-Derived Naphtha over a Commercial Hydrotreating Catalyst
Bibliographic record
Abstract
Instability associated with the presence of olefins in bitumen that is thermally processed during partial upgrading is a major concern for pipeline transportation and downstream refining. A common strategy for stabilizing thermally processed oils is to selectively hydrogenate the olefin-rich fractions, typically, the naphtha fraction (IBP–204 °C). In this paper, olefin hydrogenation was studied with hydrotreated bitumen-derived naphtha spiked with five model olefin compounds under mild hydrotreating conditions. The hydrogenation reactivities of the five model olefin/diolefin compounds are ranked in the order 1,3-hexadiene > allylbenzene > 1-heptene > 2-methyl-2-pentene > 1-methyl-cyclopentene. The reactivity is largely determined by the position of the double bond, and, to a lesser extent, by the molecular structure of the olefin. The conjugated diolefin, 1,3-hexadiene, was the most reactive. The two terminal olefins, 1-heptene and allylbenzene, were observed to be more reactive than the two olefins with internal double bonds: 2-methyl-2-pentene and 1-methyl-cyclopentene. Results also show that temperature has a significant effect on olefin hydrogenation performance, with the pressure and the liquid hourly space velocity having relatively moderate effects. Meanwhile, flash calculations confirmed the presence of vapor–liquid equilibrium under the operation conditions used. When the reactor temperature is 150 °C or less, reactions primarily occur in the liquid phase, whereas at temperatures of 200 °C or higher, the reactions occur in the vapor phase. A hydrogenation kinetics model is proposed that successfully describes the observed trends of olefin hydrogenation in the liquid phase.
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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".