The effects of multi-wall carbon nanotubes on hydrate formation
Notice bibliographique
Résumé
Clathrate hydrates are crystalline compounds that form under suitable thermodynamic conditions when inclusion molecules become trapped in a water lattice.Aside from being a hindrance to the oil and gas industry by blocking pipelines, naturally-occurring gas hydrates account for over 50% of the global carbon-based fuel reserves.This virtually untapped resource holds large potential for future extractions.In addition, the high gas storage capacity of hydrates has inspired the development of novel technologies used for transporting natural gas as well as sequestering carbon dioxide.This thesis investigates the effects of multi-wall carbon nanotubes (MWNTs) on hydrate formation.In view of optimizing hydrate-based technologies for applications including the transportation and storage of gases, the promoting effects of the MWNTs were evaluated for several hydrate systems.In order to examine the heat effects associated with adding MWNTs, an infrared camera was set up to capture the heat propagation accompanying the formation of tetrahydrofuran (THF) hydrates.The study revealed that for a given sub-cooling, the presence of hydrophobic and hydrophilic MWNTs caused an increase in the velocity of the heat front.This can be attributed to the high thermal conductivity of the MWNTs.Investigations with methane were conducted in order to model natural gas behavior.Both the dissolution phase and growth rates of the methane hydrates were examined.As-produced (hydrophobic) and plasmafunctionalized (hydrophilic) MWNTs were added at various loading concentrations to the methane and water system.It was found that the hydrophobicity of the as-produced MWNTs provided a limited dissolution and growth rate improvement, whereas their plasma-functionalized counterpart provided an enhancement at both stages of formation.This result is attributed to optimized mass transfer effects associated with the nanoparticles.Experiments with carbon dioxide were conducted under similar conditions.Two forms of MWNTs were also investigated, namely as-produced and amine-functionalized MWNTs.Due to the high solubility of carbon dioxide in water, the presence of the MWNTs did not affect the rate of dissolution as they had with the sparingly soluble methane.For the growth rate experiments, it was found that both types of the MWNTs demonstrated an enhancement, with the amine-functionalized Abstract ii MWNTs performing slightly better.Under higher concentrations however, the presence of both forms of nanoparticles produced a considerable nucleation event which induced heat and mass transfer limitations on the system.In summary, the enhancements viewed with the addition of the MWNTs can be attributed to their heat and mass transfer aiding properties.
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».