Phase Behavior of CO 2 and CH 4 Hydrate in Porous Media

Hydrate phase equilibria for the binary CO2+water and CH4+water mixtures in silica gel pore of nominal diameters 6, 30, and 100 nm were measured and compared with the calculated results based on van der Waals and Platteeuw model. At a specific temperature, three-phase hydrate-water-vapor (HLV) equilibrium curves for pore hydrates were shifted to the higher-pressure condition depending on pore sizes when compared with those of bulk hydrates. Notably, hydrate phase equilibria for the case of 100 nominal nm pore size were nearly identical with those of bulk hydrates. The activities of water in porous silica gels were modified to account for capillary effect, and the calculation results were generally in good agreement with the experimental data. The structural characteristics of gas hydrates in silica gel pores were investigated through NMR spectroscopy. Keywords—CO2, CH4, gas hydrate, equilibria.

[1]  Tsutomu Uchida,et al.  Effects of Pore Sizes on Dissociation Temperatures and Pressures of Methane, Carbon Dioxide, and Propane Hydrates in Porous Media , 2002 .

[2]  Pierre Henry,et al.  Formation of natural gas hydrates in marine sediments: 2. Thermodynamic calculations of stability conditions in porous sediments , 1999 .

[3]  Joseph W. Wilder,et al.  Interpretation of ethane hydrate equilibrium data for porous media involving hydrate‐ice equilibria , 2002 .

[4]  Ross Anderson,et al.  Experimental measurement of methane and carbon dioxide clathrate hydrate equilibria in mesoporous silica , 2003 .

[5]  Duane H. Smith,et al.  Measurements of Equilibrium Pressures and Temperatures for Propane Hydrate in Silica Gels with Different Pore-Size Distributions , 2001 .

[6]  Joseph W. Wilder,et al.  Modeling Hydrate Formation in Media with Broad Pore Size Distributions , 2001 .

[7]  Tsutomu Uchida,et al.  Methane and Carbon Dioxide Hydrate Phase Behavior in Small Porous Silica Gels: Three-Phase Equilibrium Determination and Thermodynamic Modeling , 2002 .

[8]  Y. P. Handa,et al.  Thermodynamic properties and dissociation characteristics of methane and propane hydrates in 70-.ANG.-radius silica gel pores , 1992 .

[9]  Vincent McKoy,et al.  Theory of Dissociation Pressures of Some Gas Hydrates , 1963 .

[10]  Seong-Pil Kang,et al.  Recovery of CO2 from Flue Gas Using Gas Hydrate: Thermodynamic Verification through Phase Equilibrium Measurements , 2000 .

[11]  Duane H. Smith,et al.  Resolving Apparent Contradictions in Equilibrium Measurements for Clathrate Hydrates in Porous Media , 2001 .

[12]  Huen Lee,et al.  Efficient recovery of CO2 from flue gas by clathrate hydrate formation in porous silica gels. , 2005, Environmental science & technology.

[13]  H Lee,et al.  A new hydrate-based recovery process for removing chlorinated hydrocarbons from aqueous solutions. , 2001, Environmental science & technology.

[14]  Takeshi Ishizaki,et al.  Dissociation Condition Measurements of Methane Hydrate in Confined Small Pores of Porous Glass , 1999 .

[15]  M. Clarke,et al.  A Method To Predict Equilibrium Conditions of Gas Hydrate Formation in Porous Media , 1999 .

[16]  B. Tohidi,et al.  Characteristics of Clathrate Hydrate Equilibria in Mesopores and Interpretation of Experimental Data , 2003 .

[17]  H. Teng,et al.  Why does CO2 hydrate disposed of in the ocean in the hydrate-formation region dissolve in seawater? , 1997 .

[18]  Joseph W. Wilder,et al.  Methane hydrate equilibria in silica gels with broad pore-size distributions , 2002 .

[19]  Carolyn A. Koh,et al.  Clathrate hydrates of natural gases , 1990 .

[20]  Gerald D. Holder,et al.  Thermodynamic and Molecular Properties of Gas Hydrates from Mixtures Containing Methane, Argon, and Krypton , 1980 .