Pesticides from fast pyrolysis of agricultural and forestry residues
Bibliographic record
Abstract
This thesis investigates the production of pesticides through the fast pyrolysis of three biomass feedstocks: tobacco leaves, dried coffee grounds and pinewood killed by beetles. It was observed that a significant fraction of the bio-oil escaped the condensing train as a fine mist; this is a common problem in pyrolysis operations. An electrostatic demister was, therefore, developed to recover this mist. Tobacco leaves were pyrolyzed to produce bio-oil. Pyrolysis was carried out at six different temperatures from 350°C to 600°C and at three different vapor residence times (5, 10 and 17 s), to study the effect of operating conditions on the bio-oil yield. The trends clearly indicated a strong effect of temperature and vapor residence time on the bio-oil yield. A temperature of 500°C was then selected and the pyrolyzer was operated again at the lowest vapor residence time of 5 s to obtain accurate liquid, gas and char yields. Tobacco bio-oils produced at different temperatures (350-600oC) and at a vapor residence time of 5 s were tested for their bactericidal, fungicidal and insecticidal activities against pests found on plants in Canada that currently require improved control options. A significant finding of the research was that even fractions containing no nicotine had significant activity towards the aforementioned pests. Dried coffee grounds were pyrolyzed to produce bio-oil. Pyrolysis was carried out at five different temperatures from 400°C to 600°C and at a vapor residence time of 5 s, to study the effect of temperature on the bio-oil yield. The trends clearly indicated a strong effect of temperature on the bio-oil yield. Coffee grounds bio-oils produced at different temperatures (400-600oC) were tested for their bactericidal and insecticidal activities against pests found on plants in Canada that currently require improved control options. While some compounds in the bio-oil, such as phenols, were active against both beetles and bacteria, the coffee bio-oil contained in chemicals that provided additional insecticidal activity but had no bactericidal activity. Single-stage and two-stage tubular electrostatic precipitators were designed for the recovery of bio-oil mist. Because of concerns regarding bio-oil stability, an inert fogging oil was used for the development of the demisters. A nitrogen stream containing very fine droplets of fogging oil was forced through the electrostatic precipitator chamber. It was found that 98.6 wt% of the oil droplets present in the turbulent jet were mechanically collected on the inner walls of the test chamber. When the electrode was energized at 13 K V, 92.37wt%ofthedropletsthathadnot been mechanically separated were collected in single-stage mode. The collection efficiency was increased to 93.18 wt%, when the electrostatic precipitator was operated in two-stage mode. Voltage-current (V-I) characteristics of the singlestage and two-stage electrostatic precipitators were studied in detail for different test conditions. Nitrogen impurities played a major role in determining the V-I characteristics. They became less relevant with the introduction of mist in the nitrogen stream, presumably due to the presence of water vapor in the gas. The two- stage tubular electrostatic precipitator was scaled up and tested on a fluidized bed pilot plant used for the pyrolysis of biomass. A droplet collection efficiency of 95 wt% was observed. Such demisters will extend, to the product recovery train, the process intensification gains of short residence time processes such as fast pyrolysis.
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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 | 0.000 |
| 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) | 0.001 | 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".