This work is part of a research project sponsored by the Italian Electricity Agency for CO2 disposal in form
of hydrate. The dissociation behavior of CH4 hydrate was taken as a reference for the study of the CO2
hydrate preservation. The formation and dissociation of CO2 and CO2–THF mixed hydrates, compared to
CH4 and CH4 – THF mixed hydrates, has been considered.
The experimental tests were performed in a 2 liter reaction calorimeter at pressures between 0.1 and 0.3
MPa. The dissociation has been followed at temperatures from -3 °C to 0 °C for CO2 and CH4 hydrates,
and from -3 °C to 10 °C for THF mixed hydrates.
More than pressure, which is very important for methane hydrates, temperature affects the preservation of
CO2 and CO2–THF mixed hydrates. Subcooling after formation is important for methane hydrate
preservation, but it does not substantially affect CO2 hydrate stability. In the studied P, T range, CO2
hydrate does not present any anomalous self-preservation effect. The mixtures containing more ice show a
slower dissociation rate. Methane hydrate requires less energy to dissociate than CO2 hydrate and,
therefore, is less stable. On the contrary, the mixed CO2 – THF hydrates are less stable than the mixed
methane hydrates. Modulated differential scanning calorimetry (MDSC) has been used for hydrate
characterization: both CH4 and CO2 hydrates include two decomposition peaks, the first due to the melting
of the ice and the second to the decomposition of the hydrate. The higher temperature of the decomposition
peak of CO2 hydrate confirms its higher stability respect to CH4 hydrate.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:BVAU.2429/2323 |
| Date | 07 1900 |
| Creators | Giavarini, Carlo, Maccioni, Filippo, Broggi, Alessandra, Politi, Monia |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | text |
| Rights | Giavarini, Carlo |
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