In this communication, we first report experimental hydrate dissociation pressures for the methane/ carbon dioxide + furan/ acetone/ 1,4- dioxane + water and the methane + tetra n-butyl ammonium chloride (TBAC) + water as well as the methane /carbon dioxide + tetra n-butyl ammonium floride (TBAF) + water systems in the temperature ranges of (269.9 to 303.3) K. An isochoric pressure-search method was used to generate the experimental data. The hydrate dissociation data are compared with the corresponding literature data and the predictions of a previously reported thermodynamic model and acceptable agreement is observed.
Clathrate hydrates (or gas hydrates) are crystalline solids in which water molecules form hydrogen-bonded cagelike structures, encapsulating the small molecule(s) like methane, carbon dioxide etc . The majority of gas hydrates are known to form three typical hydrate crystalline structures: structure I (sI), structure II (sII), and structure H (sH), where each structure is composed of a certain number of cavities formed by water molecules . The formation of structure H and also structure II of some heavy molecules requires the presence of large and small guest molecules . Large molecules occupy large cavities while small molecule(s) (called help gas) fill the remaining cavities . It has been reported that furan (water insoluble), acetone (water soluble) and 1,4-dioxane (water soluble .form structure II of clathrate hydrates. However, limited hydrate issociation data have been reported for the latter systems. In semi-clathrate hydrates, a part of the cage structure is broken in order to trap the large non-gaseous hydrate former ion species, e.g. tetra n-butyl ammonium+ (TBA+) in the case of semi-clathrate hydrates in the presence of TBAx aqueous solution were x could be Br-, F- and Cl-). It is known that tetra n-butyl ammonium chloride (TBAC) and tetra n-butyl ammonium floride (TBAF) form semi-clathrate hydrates However, limited information is available for the latter systems. In this communication, we eport hydrate dissociation data for the methane/ carbon dioxide + furan/ acetone/ 1,4-dioxane + water and the methane + tetra n-butyl ammonium chloride (TBAC) + water as well as the carbon dioxide + tetra n-butyl ammonium floride (TBAF) + water systems in the temperature ranges of (269.9 to 303.3) K at various concentrations of the aforementioned non-aqueous hydrate formers in aqueous solutions.
Publisher : 2nd National Iranian Conference on Gas Hydrate (NICGH)
By : Arash Kamran-Pirzaman , Amir H. Mohammadi , and Hassan Pahlavanzadeh
File Information: English Language/ 12 Page / size: 487 KB
سال : 1392
ناشر : دومین کنفرانس ملی هیدرات گاز (NICGH)
کاری از : آرش کامران-پیرزمان، امیرحسین محمدی و حسن پهلوان زاده
اطلاعات فایل : زبان انگلیسی / 12 صفحه / حجم : KB 487