In the current work, the kinetics of crystal H hydrate formation is modeled by using the chemical affinity model. The experiments were performed at constant temperatures of 274.15, 275.15, 275.65, 276.15 and 277.15 K. Methylcyclopentane (MCP) is used as sH former and methane is used as a help gas. The parameters of model (Ar and tK) are determined and the results show that the parameter of Ar/RT has a constant value at the first step and a different value at second step.These parameters were used to predicting experimental data. The results indicate that this model can predict experimental data very well at several conditions.
Natural gas hydrates are crystalline solid compounds, composed of water (host) and typical natural gas molecules (guests) such as methane, ethane under favorable thermodynamic conditions (high pressures and low temperatures). Because of hydrogen bonding, molecules of water form a structure containing cavities that can be occupied by inclusion of guest molecules with favorable shapes and sizes. Based on cavity size and shape of the guest molecule, these hydrates can form three main crystallographic structures (Structure I, II and H) . Methane is the major component in the natural gas, so it is necessary to evaluate the feasibility of methane storage in hydrate form. The best idea for methane storage in hydrate form is sI since methane can occupy both small and large cavities. Unfortunately, methane has high formation pressures. One way to overcome this problem is to fill the large cavities in structures I and II with large miscible molecules such as ethylene oxide and tetrahydrofuran; therefore, methane occupies the small 512 cavities. Similarly, for structure H, the largest cage (51268) should stabilize with a large molecule and the methane should occupy the smaller cages (512 and 435663). Lee et al. investigated on the kinetics of sH. They used Neohexane (NH), tert-butyl methyl ether (TBME) and methylcyclohexane (MCH) as the LMGSs and methane as a help gas. They concluded that the rates of hydrate formation and the induction times are dependent on the magnitude of the driving force and the type of LMGS. Tsuji et al.
Publisher : 2nd National Iranian Conference on Gas Hydrate (NICGH)
By : Masoumeh. Seyfi Mazraehno , Farshad. Varaminian , Mohsen. Vafaei Sefti and Shahin. Khosharay
File Information: English Language/ 9 Page / size: 797 KB
سال : 1392
ناشر : دومین کنفرانس ملی هیدرات گاز (NICGH)
کاری از : معصومه سیفی مزرعه نو، فرشاد ورامینیان محسن وفایی سفتی و شاهین خسروی
اطلاعات فایل : زبان انگلیسی / 9 صفحه / حجم : KB 797