Methane hydrate film growth kinetics

Freer, Erik M.; Selim, M. Sami; Sloan, E. Dendy

doi:10.1016/s0378-3812(01)00457-5

Cited by 215 publications

(259 citation statements)

References 9 publications

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“…Uchida, et al [17] argued with a heat-conduction-limited model that it is reasonable for higher growth rates to be observed with larger degree of subcoolings. This was also confirmed by a previous work of Sloan et al [18] when they found that the hydrate growth rate was proportional to the degree of subcooling, suggesting that hydrate crystallization was a continuous growth process.…”

Section: Introductionsupporting

confidence: 89%

Effects of Stirring and Cooling on Methane Hydrate Formation in a High-Pressure Isochoric Cell

Ke¹,

Svartaas²

2013

JMSE-B

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Abstract:Higher mixing rates applied to hydrate-forming liquids in laboratory cell systems are commonly assumed to cause a more thorough dispersion of newly formed hydrate nuclei from gas-liquid interface into bulk liquid. There is, however, no simple and direct correlation between stirring rate and nucleation rate. Most experimental studies on hydrate kinetics in literature have been carried out at isobaric conditions. Studies in cooled systems at isochoric conditions (temperature-dependent pressures) are in scarcity. This paper presents an experimental study on effects of varying stirring rates (220-660 rpm) and varying cooling rates (0.5-10 °C/h) on the point of spontaneous nucleation (PSN) of structure-I methane hydrate. The experiments were conducted in an isochoric system with temperature and pressure both decreasing along with the continuous cooling process. Initial growth rates after nucleation were also monitored. The results suggest that higher stirring rates lead to reduced hydrate induction time and increased hydrate growth rate. The nucleation rate appeared to be slightly reduced at the lowest stirring rate (220 rpm). The degree of sub-cooling at PSN seemed to be of a more stochastic character at cooling rates lower than at 2 °C/h. Increased cooling rates trend to reduce induction time while the sub-cooling at PSN appeared to first oscillate at lower cooling rates then approach some constant level at higher cooling rates. For higher cooling rates, the nucleation rate decreased faster. Hydrate growth behavior in cooling rate experiments (0.5-10 °C/h) suggests that the total gas intake and the gas consumption rate increased with increasing cooling rate towards a constant level at 6-10 °C/h. A careful selection of stirring rate and cooling rate is essential to hydrate study.

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Section: Introductionsupporting

confidence: 89%

Effects of Stirring and Cooling on Methane Hydrate Formation in a High-Pressure Isochoric Cell

Ke¹,

Svartaas²

2013

JMSE-B

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“…The further growth of hydrate is controlled by mass transfer of water or hydrate former through the film. Many experimental and/or theoretical studies on the growth of hydrate film have been carried out by several groups (Freer et al, 2001;Ma et al, 2002;Mochizuki and Mori, 2006;Mori, 2001;Ohmura et al, 2000Ohmura et al, , 2005Peng et al, 2007Peng et al, , 2008Peng et al, , 2009Saito et al, 2010Saito et al, , 2011Sun et al, 2007;Taylor et al, 2007;Uchida et al, 1999Uchida et al, , 2002, including the morphology of hydrate film, the growth rate of hydrate film, the thickness of hydrate film, the mechanism of hydrate film growth, and so on. However, so far it is still a controversial topic on the growth mechanism of hydrate film.…”

Section: Heat Transfer In Growth Of Hydrate Filmmentioning

confidence: 99%

“…For investigating the growth mechanism of the hydrate film, Freer et al (2001) also studied methane hydrate film growth on the water/methane interface experimentally and proposed a model of lateral hydrate film growth. They calculated the f v of methane hydrate film by assuming that one dimensional conductive heat transferred from the film front to water.…”

Section: Hydrate Film Growthmentioning

confidence: 99%

“…However, in this model Peng et al kept the hydrate film at S T rather than at the three-phase (water/guest/hydrate) equilibrium temperature and they proposed the intrinsic rate of hydrate film growth should not be of a linear relation with the driving force. Therefore, the balance of the heat removed from the film front with that generated by the hydrate formation was formulated by the equation proposed by Freer et al (2001),…”

Section: Hydrate Film Growthmentioning

confidence: 99%

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Heat Transfer Related to Gas Hydrate Formation/Dissociation

Liu¹,

Pang²,

Peng³

et al. 2011

Developments in Heat Transfer

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“…As some research groups have pointed out, an increase of degree of subcooling would lead to increasing hydrate growth rate [22][23]. To compare growth rates at the various values γ m examined, experiments with comparable ∆T values at PSN were therefore selected for calculation and comparisons.…”

Section: Hydrate Growthmentioning

confidence: 99%

The Effect of Molar Liquid Water-Gas Ratio on Methane Hydrate Formation

Ke¹,

Svartaas²

2013

JMSE-B

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Experimental results and analysis among different hydrate research groups are very often not transplantable, partly due to the intrinsic stochastic nature of hydrate formation, partly due to different experimental conditions, gas compositions and analyzing techniques used or applied. In the present work the effect of the molar liquid water-gas ratio (γ m ) on both nucleation and growth of methane hydrate has been examined. Structure I methane hydrates were formed under isochoric conditions in stirred cell during constant cooling, and the point of spontaneous nucleation (PSN) was recorded. The results show that change of γ m gave no significant effect on average induction time, average nucleation rate or average sub-cooling at PSN. Nevertheless, nucleation behaved more stochastic when the volume fraction of water and γ m increased. Moderate γ m values that were closer to the theoretical hydration number (5.9 to 6 at the experimental conditions) could achieve larger total gas consumption and higher hydrate formation rate. "Imbalanced" γ m values (either highly water-excess or highly gas-excess) may however lead to smoother behavior of crystal growth.

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Methane hydrate film growth kinetics

Cited by 215 publications

References 9 publications

Effects of Stirring and Cooling on Methane Hydrate Formation in a High-Pressure Isochoric Cell

Effects of Stirring and Cooling on Methane Hydrate Formation in a High-Pressure Isochoric Cell

Heat Transfer Related to Gas Hydrate Formation/Dissociation

The Effect of Molar Liquid Water-Gas Ratio on Methane Hydrate Formation

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