Direct Coal Liquefaction: Low Temperature Dissolution Process
Bibliographic record
Abstract
The front-end design of a direct coal liquefaction process for the conversion of lignite into coal liquids by solvent extraction was investigated. The experimental work focused on physical coal dissolution in the temperature range 25–150 °C. It was found that the kinetics of physical coal dissolution was rapid and essentially complete within 2 min at 25 °C. There was a limiting extract yield, which increased with increasing temperature. Within the pore diameter range 0.1–10.7 μm, the volume of only pores with diameters <5 μm increased measurably on solvent extraction, while the shape of the pore size distribution remained the same. Additional pore volume created during extraction exceeded that of the liquid extract. Extraction took place from the bulk of the coal. Packed bed extraction was more efficient than batch extraction at otherwise similar conditions; an explanation was proposed. Even at the least severe conditions, 25 °C for 2 min, mass transport was not limiting and the solvent-to-coal ratio did not meaningfully affect the extract yield. These observations were employed to propose potential improvements to the front-end design for direct coal liquefaction.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 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".