Exothermicity in wood torrefaction and its impact on product mass yields: From micro to pilot scale
Bibliographic record
Abstract
This paper focuses on the effects of exothermic reactions during torrefaction, a mild heat treatment process in the temperature range 200 to 300 °C. Three different scales are considered, the micro‐particle (powder scale), the macro‐particle (woodchips or larger) and the thick fixed bed (pilot reactor) together with three wood types, spruce, beech and locust. At the powder scale, TGA‐DSC tests indicate that exothermic reactions are noticeable principally during the first stages of torrefaction. The mass loss kinetics are used to evaluate parameters for a DAEM (Distributed Activation Energy Method) model. At the macro‐particle scale, temperature measurements within wood planks heated in an oven depict the presence of temperature overshoots due to the exothermic reactions that lead to unevenly treated particles. At the reactor scale, a large fixed bed of wood chips is heated in the same oven by an up‐flowing recirculated mixture of inert gas and volatiles. The exothermic reactions are found to generate a heat wave that propagates up the bed. Total mass losses are found to largely exceed those predicted with the DAEM model based on recorded bed temperatures. This means that, in order to reach the measured mass yields, the inner core temperatures of the wood chips must be higher than those of their outer surface and of the gas flow. Multi‐scale modelling approaches are therefore required to take into account the combined exothemicity and diffusional limitations within the wood chips and at their exchange surfaces.
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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".