Single Particle Asphaltene Pyrolysis in a Drop-Tube Furnace
Bibliographic record
Abstract
Oil sands in the Athabasca and Cold Lake regions of Northern Alberta form Canada’s primary source of energy reserves. Asphaltenes, a significant part of bitumen, are often considered to be the least valuable component of crude oil due to various factors such as difficulty in transporting and processing. Very few studies have been carried out on the pyrolysis of asphaltenes in entrained flow conditions. Single particle investigations are useful since they are conducted in a well-controlled environment allowing for the elimination of complexities arising from particle–particle interactions. Char is an intermediate of the gasification process, and the structural and morphological behavior of char plays a pivotal role in determining the rate of gasification. In this work, the pyrolysis of pulverized asphaltene feedstock was carried out in a tube furnace maintained at atmospheric pressure. The effects of furnace temperature and particle size on char formation and char characteristics were investigated. Chars obtained from larger particles (1.7 mm to 850 μm) exhibited morphology similar to that of asphaltene particles while the pyrolysis of particles ranging from 250 to 425 μm at higher temperatures resulted in char with less volatile matter remaining. Scanning electron microscope (SEM) and cross-sectional images of char particles indicated the formation of cenospheres and the fragmentation of char particles at higher pyrolysis temperatures. High pyrolysis temperatures also led to a loss of active sites, an increase in alkene content, and aromatic condensation. Inductively coupled plasma mass spectroscopy (ICP-MS) and X-ray fluorescence (XRF) investigations validated the retention of K and Na along with heavy elements such as V, Ni, and Cu in char at temperatures above 700 °C. Ultimately, the combustion reactivities of char were obtained at 700, 800, and 900 °C for particles of 425–850, 355–425, and 250–355 μm, respectively, and were compared using the Flynn Wall Ozawa method.
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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 | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".