در سال‌های اخیر ایده استفاده از هیدرات گاز طبیعی برای ذخیره‌سازی و انتقال گاز مطرح شده است. بدین علت که می‌توان آن را در دمایی بسیار بالاتر از گاز طبیعی مایع شده، تولید و منتقل نمود. هدف اصلی در این تحقیق بررسی تأثیر مواد فعال سطحی غیر یونی Tween-20 و Tween-800 بر روی سرعت تشکیل هیدرات متان و ظرفیت ذخیره‌سازی آن است. Tween-20 با غلظت‌های 1000 و ppm 2000 و Tween-80 با غلظت‌های 100 و ppm 500 به کارگرفته شده و نتایج با هیدرات تشکیل شده در آب خالص و محلول آبی با غلظت ppm 500 از SDS مقایسه شده است. غلظت‌های مختلف مواد فعال سطحی غیر یونی، اثرات متفاوتی بر روی سرعت تشکیل هیدرات و ظرفیت ذخیره‌سازی آن داشت. از این تحقیق نتیجه گرفته شد که ppm 2000 از Tween-20، سرعت تشکیل هیدرات و ظرفیت ذخیره‌سازی آن را بالا می‌برد. این درحالی است که وقتی ppm 1000 از این ماده به کار گرفته شد، به صورت مؤثری از تشکیل هیدرات جلوگیری کرد. Tween-80 در هر دو غلظت به کار رفته، سرعت تشکیل هیدرات را کم کرد و بیشترین ظرفیت ذخیره‌سازی مربوط به ماده Tween-20 با غلظت ppm 2000 بود که برابر (V/V) 125 به دست آمد.
Effect of Non-ionic Surfactants on Methane Hydrate Formation Rate and Storage Capacity
چکیده [English]
In recent years, using natural gas hydrates (NGH) for storage and transportation of gas has been considered because gas hydrates can be stored and transported at temperatures much higher than liquefied natural gas (LNG). The major objective of this study is to investigate the effects of non-ionic surfactants polysorbate 80 (Tween-80) and polysorbate 20 (Tween-20) on the formation rate and storage capacity of methane hydrate. Tween-20 was tested with 2 concentrations of 1000 and 2000 and Tween-80 was tested with 100 and 500 ppm and compared with the hydrate formed in pure water and aqueous sodium dodecyl sulfate (SDS) solution. The hydrate formation rate and the storage capacity were influenced by the different concentrations of surfactants and it was found that Tween-20, when prepared with 2000 ppm, speeded up the hydrate formation rate and increased its storage capacity; but when it was prepared with 1000 ppm, it inhibited the hydrate formation effectively. Tween-80 decreased the hydrate formation rate in both of the solutions. Experimental results on hydrate gas content revealed that the maximum storage capacity of 125 V/V is obtained with 2000 ppm of Tween-20 in water.
کلیدواژه ها [English]
Gas Hydrates, Non-ionic Surfactants, Formation Rate, Storage Capacity
مراجع
مراجع
[1] Khokar A. A., Gudmundssom J. S. and Sloan Jr E. D., “Gas Storage in Structure H Hydrates”, Fluid Phase Equilibria Volumes 150-151, pp. 383-392, 1998.
[2] Sloan E. D., “Clathrate Hydrates of Natural Gases”, 3rd ed., New York: Taylor & Francis Group, 2008.
[3] Sloan E. D., “Clathrate Hydrates of Natural Gases”, 2nd ed., Marcel Dekker, New York, 1998.
[4] Benesh M. E., The Use of Gas Hydrates in Improving the Load Factor of Gas Supply Systems, US Patent: 2270016, 1942.
[5] 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.
[6] Stern L. A, Circone S. and Kirby S. H., “Anomalous preservation of pure methane hydrate at 1 atm”, J. Phys. Chem. B, Vol 105, pp.1756-62, 2001.
[7] Giavarini C. and Maccioni F., “Self-preservation at low pressures of methane hydrate with various gas contents”, Ind. Eng. Chem. Res., 43, pp. 6616-21, 2004.
[8] Nazari K., Rahimi H., Khodafarin R., Kameli M. and Brijanian H., Stabilization of gas hydrates, EP: 2 031 044 A1, 2009.
[9] Ohmura R., Kashiwazaki S., Shiota S, Tsuji H. and Mori YH., “Structure-I and structure-H hydrate formation using water spraying”, Energy Fuels, Vol. 16. pp. 1141–1147, 2002.
[10] Han X., Wang S., Chen X. and Liu F., “Surfactant accelerates gas hydrate formation”, 4th International Conference on Gas Hydrates, Yokohama, Japan, pp. 1036–1039, 2002.
[11] Karaaslan U., Uluneye E. and Parlaktuna M., “Effect of an anionic surfactant on different types of hydrate structures”, J. Pet. Sci. Eng., Vol. 35, pp. 49–57, 2002.
[12] Sun Z. G., Wang R., Ma R., Guo K. and Fan S., “Natural gas storage in hydrate with the presence of promoters”, Energy Con.Manag., Vol 44, pp 2733–2742, 2003.
[13] Sun Z. G., Ma R. S., Wang R. Z, Guo K. H. and Fan S. S., “Experimental studying of additives effects on gas storage in hydrate”, Energy Fuels, Vol 17, pp 1180–1185, 2003.
[14] Ganandran N. and Amin R., “The effect of hydrotropes on gas hydrates formation”, J. Pet. Sci. Eng., Vol 40, pp. 37–46, 2003.
[15] Ganji H., Manteghian M., Sadaghiani Zadeh K., Omidkhah M. R. and Rahimi Mofrad H., “Effect of different surfactants on methane hydrate formation rate”, stability and storage capacity, Fuel, Vol 86, pp. 434–441, 2007.
[16] Guo Y., Fan S., Guo K. and Chen Y., “Storage Capacity of Methane in Hydrate Using Calcium Hypochlorite as Additive”, 4th international Conference on Gas Hydrates, Yokohama, pp. 1040-1043, 2002.
[17] Makogon Y. F., “Hydrates of hydrocarbons”, 1st ed., Tulas, Oklahoma: penwell Books. pp. 35-37, 1997.
[18] Lin W, Chen G. J., Sun C. Y., Guo X. Q., Wu Z. K., Liang M. Y. and et al. “Effect of surfactants on the formation and dissociation behavior of methane hydrate”, Chem. Eng. Sci., Vol 59, pp. 4449-4455, 2004.
[19] Rosen M. J., Surfactants and Interfacial Phenomena, 2nd Edition. New York, Wiley, 1989.
[20] Zhong Y. and Rogers R, “Surfactant Effects on Gas Hydrate Formation”, Chem. Eng. Sci., Vol 55, pp. 4177-41 87, 2000
[21] Daimaru T., Yamasaki A. and Yanagisawa Y., “Effect of surfactant carbon chain length on hydrate formation kinetics, Journal of Petroleum Science and Engineering”, Vol. 56, pp. 89–96, 2007.
[22] Clarke M. A. and Bishnoi P. R, “Measuring and Modelling the Rate of Decomposition of Gas Hydrates Formed From Mixtures of Methane and Ethane”, Chem. Eng. Sci., Vol 56, pp. 4715-4724, 2001.
[23] Zhang C. S., Fan S. S., Liang D. Q. and Guo K. H., “Effect of additives on formation of natural gas hydrate”, Fuel, Vol 83, pp. 2115–2121, 2004.
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