تشکیل هیدرات متان در شرایط ملایم‌تر با استفاده از تسهیل‌کننده‌های ترمودینامیکی

نوع مقاله : مقاله پژوهشی

چکیده

فشار بالای تشکیل هیدرات‌های گازی مهمترین عامل منفی در تولید انبوه هیدرات برای ذخیره‌سازی و انتقال گاز می‌باشد. در این مقاله جهت تشکیل هیدرات در فشار پایین‌تر، اثر دو ماده، تتراهیدروفوران و تتراهیدروپیران در غلظت‌های متفاوت بر نمودار تعادلی تشکیل هیدرات متان بررسی شد. چهار محلول آبی با غلظت‌های 1، 5/2 و 6 درصد مولی از تتراهیدروفوران و 6 درصد مولی از تتراهیدروپیران تهیه و نمودار تعادلی تشکیل هیدرات متان در آن رسم شد. نتایج مشخص نمود که با استفاده از این مواد، هیدرات متان در شرایط بسیار مناسب‌تری از دما و فشار تشکیل می‌شود. در حالیکه فشار تعادلی تشکیل هیدرات متان در دمای 293 درجه کلوین حدود MPa 34 است، با افزودن ماده تتراهیدروفوران با غلظت 5/2 درصد مولی این فشار به حدود MPa 49/2 کاهش یافت که 6/92 درصد کاهش را نشان می‌دهد. همچنین در فشار MPa 5 دمای تعادلی هیدرات متان حدود 278 درجه کلوین است درحالی که در همین فشار دمای تعادل فازی محلول 6 درصد مولی تتراهیدروفوران حدود 306 درجه کلوین بود.

کلیدواژه‌ها


عنوان مقاله [English]

Formation of Methane Hydrate under Milder Conditions Using Suitable Thermodynamic Promoters

چکیده [English]

High formation pressure is the most critical problem hindering formation of gas hydrates in industrial scale for storage and transportation of natural gas. The effects of tetrahydrofuran (THF) and tetrahydropyran (THP) on the phase equilibrium of methane hydrate have been studied. The addition of THF at different concentrations of 1, 2.5 and 6 mol % and THP at 6 mol % aqueous solutions caused hydrate equilibrium pressure to drastically reduce at a specified temperature. While the equilibrium pressure of methane hydrate is about 34 MPa at 293K, this equilibrium pressure decreased to about 2.5 MPa using 2.5 mol % of THF. Furthermore, the hydrate equilibrium temperature greatly increased at a specified pressure. The equilibrium temperature of methane hydrate at 5 MPa is about 278K. This equilibrium temperature increased to about 306K using 6 mol % of THF.

کلیدواژه‌ها [English]

  • Gas Hydrate
  • Phase Equilibrium
  • Thermodynamic Promoter
منابع
[1] Makogon Y. F., Holditvh S. A. & Makogon T. Y., “Natural gas hydrates- A potential energy source for the 21st Century”, J. of Pet. Sci. and Eng., Vol. 56, pp.14-31, 2007.
[2] Englezos P., “Clathrate Hydrate”, Ind. Eng. Chem. Res.,Vol. 32, pp.1251-1274,1993.
[3] Clarke M. & Bishnoi P.R., “Determination of the intrinsic rate of ethane gas hydrate decomposition”, Chem. Eng. Sci., Vol. 55, pp.4869-4883,2000.
[4] Sloan E. D., Clathrate hydrate of natural gases, 2nd Ed., New York, Marcel Dekker Inc., 1997.
[5] Karaaslan U. & Parlaktuna M., “Promotion effect of polymers and surfactants on hydrate formation rate”, Energy & Fuels, Vol. 16, pp.1413-1416, 2002.
[6] Max M. D. & Pellenbarg R. E., Desalination through methane hydrate, U. S. Patent: 5873262, 1999.
[7] Javanmardi J. & Moshfeghian M., “Energy consumption and economic evaluation of water desalination by hydrate phenomenon”, App. Therm. Eng. , Vol. 23, No. 7, pp. 845-857, 2003.
[8] Kang S. P. & Lee H., Recovery of CO2 from Flue Gas Using Gas Hydrate: “Thermodynamic Verification through Phase Equilibrium Measurements”, Environ. Sci. Technol.,Vol. 34, No. 20, pp. 4397–4400, 2000.
[9] Benesh M. E., The use of gas hydrates in improving the load factor of gas supply systems, US Patent: 2270016, 1942.
[10] Handa Y., “Calorimetric determination of The compositions, enthalpies of dissociation and heat capacities in the range of 80 to 270K for clathrate hydrates of xenon and krypton”, J Chem. Therm., Vol. 18, pp. 891-903, 1986.
[11] Giavarini C. & Maccioni F., “Self-preservation at low pressures of methane hydrate with various gas contents”, Ind. Eng. Chem. Res., Vol. 43, pp.6616-6621, 2004.
[12] Gudmundsson J. S. & Hveding F., Borrehaug A., Transport of natural gas as frozen hydrate, 5th Intnl. offshore and polar engineering conf. Netherlands, 1995.
[13]Gudmundsson J. S. & Mork M., Stranded gas to hydrate for storage and transport, Intnl. gas research conf., Amsterdam, 2001.
[14] Miata K., Okui T., Hirayama H & Ihara M., A challenge to high-rate industrial production of methane hydrate, Proc 4th Intnl. Conf. on natural gas hydrates, Yokohama, Japan , pp. 1031-1035, 2002.
[15] Sun Z., Wang R., Ma R., Guo K. & Fan S., “Natural gas storage in hydrate with the presence of promoters”, Energy Conv. Manag., Vol. 44,pp. 2733-2742, 2003.
[16] Ganji H., Manteghian M., Sadaghiani K., Omidkhah M. R. & Rahimi mofrad H., “Effect of different surfactants on methane hydrate formation rate”, stability and storage capacity, Fuel, Vol. 86, pp. 434-441,2007.
[17] Ganji H., Manteghian M. & Rahimi mofrad H., “Effect of mixed compounds on methane hydrate formation and dissociation rates and storage capacity”, Fuel Processing Technology, Vol. 88, pp. 891-895,2007.
[18] Gudmundsson J. S. & Brrehaug A., Frozen hydrate for transport of natural gas, Proc 2nd Intnl. Conf. on natural gas hydrates. Toulouse, France, pp.415-442,1996.
[19] Fitzgerald A., Taylor M., “Offshore Gas-to-Solid technology”, SPE Paper 71805, Presented at the Offshore Europe Conference held in Aberdeen, UK, pp. 4-7,2001.
20] Kang S. P., Lee H., Lee C. S. & Sung W. M., “Hydrate phase equilibria of the guest mixtures containing CO2, N2 and tetrahydrofurane”, Fluid Phase Equilibria., Vol.185, pp.101-109, 2001.
[21] Florusse L. J., Peters C. J., Schoonman J., Hester K. C., Koh C. A., Dec S. F., Marsh K. N. & Sloan E. D., “Stable low-pressure hydrogen clusters stored in a binary clathrate hydrate”, Science, Vol. 306, pp.469-471, 2004.
[22] Zhang Q., Chen G. J., Huang Q., Sun C. Y., Guo X. Q. & Ma Q. L., “Hydrate formation condition of a hydrogen + methane gas mixture in tetrahydrofuran + water”, J. Chem. Eng. Data, Vol. 50 pp.234-236, 2005.
[23] Linga P., Kumar R. & Englezos P., “Gas hydrate formation from hydrogen/ carbon dioxide and nitrogen/ carbon dioxide gas mixtures”, Chem. Eng. Sci., Vol. 62, pp.4268-4276, 2007.
[24] Sun C. Y., Ma C. F., Chen G. J. & Zhang S. X., “Experimental and simulation of single equilibrium stage separation of (methane+ hydrogen) mixtures via forming hydrate”, Fluid Phase Equilibria, Vol. 261, pp.85-91, 2007.
[25] Rovetto L. J., Storbel T. A., Koh C. A. & Sloan E. D., “Is gas hydrate formation thermodynamically promoted by hydrotrope molecules?”, Fluid Phase Equilibria, Vol 247, pp.84-89,2006.
[26] Tohidi B., Burgass R. W, Danesh A., Qstergaard K. K. & Todd A. C., “Improving the Accuracy of Gas Hydrate Dissociation Point Measurements”, Annals of the New York Academy of Sciences, Vol. 912, pp.1412-1419, 2000.[27] HWHYD software, Herriot Watt University, UK.
[28] Gough S. R. & Davidson D. W., “Composition of tetrahydrofuran hydrate and the effect of pressure on the decomposition”, Can. J. Chem. ,Vol. 49, pp. 2691-2699, 1971.
[29] Hashimoto S., Sugahara T., Moritoki M., Sato H. & Ohgaki K., “Thermodynamic stability of mixed gas hydrate containing hydrogen”, J. of Physics: Conference Series, Vol. 121, 022012, 2008.
[30] Storbel T. A., Koh C. A. & Sloan E. D., “Hydrogen storage properties of clathrate hydrate materials”, Fluid Phase Equilibria, Vol. 261, pp. 382-389, 2007.