Study of the Methane Hydrate Stability Under Various State of Temperature and Pressure

Document Type : Research Article


Faculty of Chemical Engineering, Tarbiat Modares University, P.O. Box 14115-143 Tehran, I.R. IRAN


Since The stability of methane hydrate is vital for storage and transport of natural gas, the effects of temperature and initial gas content on the dissociation rate of methane hydrate have been investigates. In order to formation of hydrate with various initial gas contents, the formation experiments have been accomplished in different condition. After formation of hydrate, the dissociation experiments have been performed at atmospheric pressure, different temperatures (ranging from 270.2 K to 262.2 K) and various initial gas  in hydrate (n0=0.03 & n0=0.06). In constant temperature, the results show that the dissociation rate and instability of hydrate decreases, because an ice layer covers the hydrate surface. This phenomenon is called self-preservation effect of gas hydrate. Also the dissociation rate decreases with reduction of temperature. Increase in the initial gas content in hydrate, results in the increment of the dissociation percentage of hydrate, since the quantity of ice has been reduced in the system. A model has been developed for prediction of methane hydrate dissociation percent by correlating the experimental data received from the related experiments.  


Main Subjects

[1] Grauls D., Gas hydrates: Importance and Applications in Petroleum Exploration, Marin and Petroleum Geology, 18, p. 519 (2001).
[2] Sloan E.D, Clathrate Hydrate Measurements: Microscopic, Mesoscopic, and Macroscopic, J. Chem Thermo, 35, p. 41 (2003).
[3] Sloan E.D, "Clathrate Hydrates of Natural Gases", 2nd ed., Mrcel Dekker NewYork, (1998).
[4] Clarke M., Bishnoi P., Measuring and Modeling the Rate of Decomposition of Gas Hydrates Formed from Mixtures of Methane and Ethane, Chem Eng Sci, 56, p. 4715 (2001).
[5] Masaki O. et al, Methane Recovery from Methane Hhydrate Using Pressurized CO2, Fluid Phase Equilibria, 228, p. 553 (2005).
[6] Ahmadi G., Ji C., Smith H., Numerical Solution for Natural Gas Production from Methane Hydrate Dissociation, Journal of Petroleum Science and Engineering, 41(4), p. 269 (2004).
[7] Giavarini C. Maccioni F, Self-Preservation at Low Pressure of Methane Hydrates with Various Gas Contents, Ind. Eng. Chem. Res., 43, p. 6616 (2004).
[8] Giavarini C. Maccioni F, Politi M., Sntarelli M.L., CO2 Hydrate: Formation and Dissociation Compared to Methane Hydrate, Energy & Fuels, 21, p. 3284 (2007).
[9] Shirota H., Aya I., Namie S., Varam B., Turner D., Sloan E.D., "Measurement of Methane Hydrate Dissociation for Application to Natural Gas Storage and Transportation", Proceedings of the 4th International Conference on Gas Hydrates, Yokohama, Japan, (2002).
[10] Ji C., Ahmadi G., Smith H., Natural Gas Production from Hydrate Decomposition by Depressurization, Chem Eng Sci, 56(20), p. 5801(2001).
[11] Tarek A., "Hydrocarbon Phase Behaviore", First Edition,(1946).
[12] Kim H.C., Bishnoi P.R., Heideman R.A., Rizvi S.S.H., Kinetics of Methane Hydrate Decomposition, Chem Eng Sci, 42, p. 1645 (1987).
[13] Clarke M., Bishnoi P., Determination of the Intrinsic Rate of Ethane Gas Hydrate Decomposition, Chem Eng Sci, 55, p. 4869 (2000).
[14] Goel N., Wiggins M., Shah S., Analytical Modeling of Gas Recovery from in Situ Hydrates Dissociation, Journal of Petroleum Science and Engineering, 29, p. 115 (2001).