Life cycle GHG emissions assessment of vanadium recovery from bitumen-derived petcoke fly ash
Bibliographic record
Abstract
Petcoke generated during bitumen upgrading is a potential source of vanadium for the global market. Recovering vanadium from the fly ash originating from the combustion of petcoke appears to be a suitable route for commercial implementation, given its high extraction rate. Although the technical feasibility of the recovery process has been proven, the environmental impact should be addressed. Information on the greenhouse (GHG) emissions from the process is scarce in the public domain. Therefore, a framework was developed for assessment of life cycle GHG emissions for extraction of vanadium from petcoke-based fly ash. This framework was used to perform a life cycle GHG emissions assessment of a water leaching and salt roasting process to extract vanadium from fly ash. For the upstream GHG emissions, we collected direct emissions data and energy consumption from the literature, and, for the process emissions, we developed a model to estimate energy and material balances based on process conditions. The emission factors for electricity production, fuel combustion, production of consumables, and gas treatment were used to obtain the life cycle GHG emissions. The results show that the life cycle GHG emission of vanadium recovery are 26.6 − 3.9 + 0 . 9 kg CO 2 eq/kg V 2 O 5 ; 66% of these are direct GHG emissions. The process GHG emissions from fly ash decarbonization contribute the most to the life cycle GHG emissions. The air-to-fuel ratio for roasting and the GHG emission factors for petcoke combustion and the gas treatment operation are the inputs that most effect the model output. Compared with the production of V 2 O 5 from vanadium titano-magnetite ore and bitumen upgrading spent catalyst, the petcoke fly ash pathway generates about twice the life cycle GHG emissions. This study's results can help determine areas of improvement in the upstream operations and the recovery process to reduce the life cycle GHG emissions to levels that can compete with primary and alternative routes to produce vanadium pentoxide. The results of this study can help in decision-making associated with vanadium extract from fly ash produced from combustion of petcoke. • The life cycle GHG emission of vanadium recovery are 26.5 − 3.8 + 1.0 kg CO 2 eq/kg V 2 O 5 . • 67% of the life cycle GHG emissions are due to process emissions. • Fly ash decarbonization contributes the most to life cycle GHG emissions. • GHG emissions doubled those from VTM ore and bitumen upgrading spent catalyst pathways.
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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) | 0.002 | 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 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".