Effect of Surface Energy on Carbon Dioxide Hydrate Formation
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- 作者：Junfang Zhang ; Mauricio Di Lorenzo ; Zhejun Pan
- 刊名：The Journal of Physical Chemistry B
- 出版年：2012
- 出版时间：June 21, 2012
- 年：2012
- 卷：116
- 期：24
- 页码：7296-7301
- 全文大小：396K
- 年卷期：v.116,no.24(June 21, 2012)
- ISSN：1520-5207
文摘
In this work, the effect of the surface energy between the hydrate clusters and the aqueous phase on the hydrate formation of carbon dioxide was thoroughly investigated. Our results show that the threshold pressure for hydrate formation is less sensitive to the temperatures if the surface energy is not larger than 7mJ/m2. However, the threshold pressure is very sensitive to the temperatures and increases significantly with the surface energy if it is over 7, 9, and 10 mJ/m2 for the temperatures of 279, 277.45, and 276 K, respectively. The value of the surface energy for the CO2 hydrate/water system was determined as 9.3 mJ/m2 by comparing our results with the experimental data for stable CO2 hydrate formation at the temperature range of 277.45鈥?78.85 K and at pressures of 55鈥?65 bar. This value is very close to the recently reported value of 7.5 卤 1.4 mJ/m2 from molecular simulation. A theoretical method was proposed for computing the induction time of hydrate formation adopting a composite of the time required for critical nuclei formation and their growth to a detectable size. By using this method, the surface energy was avoided in the induction time calculation and an average crystallite volume of 0.238 mm3 at the induction time was derived based on the experimental data. It provides an approach for predicting the induction time for gas hydrate formation.