Clathrate hydrates formation

A rather nnexpected solnbilization phenomenon has also been described, i.e., the pressnre-indnced encapsnlation of low-molecnlar-weight gases in the aqneons micellar core, followed by clathrate hydrate formation [144,145],... 

Mochizuki, T. (2003). Clathrate hydrate formation at liquid/liquid interface under shear water flow. J. Crystal Growth, 249, 372-380. 

Ohmura, R. Uchida, T. Takeya, S. Nagao, J. Minagawa, H. Ebinuma, T. Narita, H. (2003 a). Clathrate hydrate formation in (methane + water + methylcyclohexanone) systems the first phase equilibrium data. J. Chem. Thermodynamics, 35, 2045-2054. 

Zeng, H. Wilson, L.D. Walker, V.K. Ripmeester, J.A. (2003). The inhibition of tetrahydrofuran clathrate-hydrate formation with antifreeze protein. Can. J. Phys., 81 (1-2), 17-24. 

Nguyen, H.T., Clathrate Hydrate Formation and Protein Solubilization in Reversed Micelles, Ph.D. Thesis, Tulane University, LA (1991). 

Turner, D., Clathrate Hydrate Formation in Water-in-Oil Dispersions, Golden, Colorado School of Mines, Golden, CO (2005). 

Figure 6.4 (a) ExxonMobil flow loop for hydrate formation, before installing the FBRM instrument, peripheral equipment and housing. (From Turner, D., Clathrate Hydrate Formation in Water-in-Oil Dispersions, Ph.D. Thesis, Colorado School of Mines, Golden, CO 2005. With permission.) (b) Flow wheel apparatus for hydrate formation during flow simulation. (Reproduced from Bakkeng, S.E., Fredriksen, A.E., in Proc. First International Conference on Natural Gas Hydrates, 715, 502 (1994). With permission from the New York Academy of Sciences.)... 

COLOR FIGURE 8.8 Plug formation via aggregation in an oil-dominated system. (From Turner, D.J., Clathrate Hydrate Formation in Water-in-Oil Dispersions, Ph.D. Thesis, Colorado School of Mines, Golden, CO (2004). With permission.)... 

With the growth of the oil and gas industry in the USA, it was realised as early as 1934 that the blocking of gas pipelines at temperatures where normal water would not freeze was being caused by clathrate hydrate formation. The combination of water and hydrocarbons at low temperature, and often increased pressure, are ideal conditions for hydrate formation. Much understanding of this phenomenon has been gained since that time, but as drilling and transportation conditions become more extreme, clathrate hydrate formation continues to be a major problem and is still a very active area of research. 

Figure 3.3 Pressure-temperature diagram of hydrogen clathrate hydrate formation with different promoters [22].

Carlo simulation of ice-crystal growth to study the mechanism of inhibition of AFPs on the surface of the THF hydrate and propane hydrate. They found that most of the octahedron surfaces of the THF hydrate were covered with AFP molecules, which could reduce the growth rate of the THF hydrate only allowing plate growth perpendicular to that surface. It is thus necessary to look for other experimental evidences to clarify the common features of AFPs on the inhibition of the clathrate hydrate formation. 

K. Iwasaki and T. Fujiyama, Light-scattering study of clathrate hydrate formation in binary mixtures of tert-butyl alcohol and water. 2. Temperature effect. J. Phys. Chem., 83 (1979), 463-468. 

Henning, R.W. Schultz, A.J. Thieu, V. Halpem, Y. Neutron diffraetion studies of CO2 clathrate hydrate Formation from deuterated ice. J. Phys. Chem. A 2000, 104, 5066-5071. 

Figure 41 Static permittivity vs. time for clathrate hydrate formation in model W/O emulsions. The concentrations of CCI3F in H2O were 0.80, 0.90, 1.00, and 1.20, respectively, times the theoretical molar fraction 1 17 expected to be found in the hydrates. (From Ref. 179.)...

Figure 42 Relaxation time vs. time during clathrate hydrate formation. (From Ref. 179.)...

The mechanism of clathrate hydrate formation shows similarities to adsorption of molecules at sites on a surface. The assumptions made for the mechanism of Langmuir adsorption are also applicable for hydrate formation [2]. The occupancy of the sites on a surface in the Langmuir adsorption theory is given by a so-called Langmuir isotherm, which can also be developed for the occupancy of the cavities in clathrate hydrates. 

Henning RW, Schultz AJ, Thieu V, Halpem Y (2000) Neutron diffraction studies of C02 clathrate hydrate formation Irom deuterated ice. J Phys Chem A 104(21) 5066—5071... 

Figure 28 The seven dominant cages in incipient clathrate hydrate formation as observed from molecular dynamics simulations. The four most common cages to form in the incipient solids are shaded more prominently (5 2, 4 5 62, 5 62, 5 262). Horizontal and diagonal arrows indicate a transformation via addition or removal of a pair of water molecules, while vertical arrows represent a transformation via rotation of a pair of water molecules. Adapted from Ref. 123.

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