Metastable states during dissociation of carbon dioxide hydrates below 273K

Melnikov, V. P.; Nesterov, A. N.; Reshetnikov, A. M.; Истомин, В. А.

doi:10.1016/j.ces.2010.10.007

Cited by 59 publications

(44 citation statements)

References 12 publications

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“…Reversible dissociation of metastable hydrates into supercooled water and gas It was previously shown using optical spectroscopy that metastable hydrates could grow on the surface of single small droplets of supercooled liquid water or dissociate into supercooled water and gas below the pressure of the L sw -H-G metastable equilibrium (Melnikov et al, 2010(Melnikov et al, , 2011. Below, data on the behaviour of bulk Freon-12 hydrate in the region of its metastability obtained from NMR measurements are presented.…”

Section: Resultsmentioning

confidence: 98%

“…Subsequently, the possibility of hydrate dissociation into supercooled water and gas was confirmed for the hydrates of methane, ethane, carbon dioxide, and Freon-12 (CCl 2 F 2 ) using optical microscopy observations (Melnikov et al, 2009(Melnikov et al, , 2010(Melnikov et al, , 2011, Raman (Ohno et al, 2011) and pulsed NMR (Melnikov et al, 2012 spectroscopy, and differential thermal analysis (DTA) Melnikov et al, 2015). Hence, we can conclude that the possibility gas hydrates dissociating below the ice melting point into supercooled water and gas is a universal property common to gas hydrates.…”

Section: Introductionmentioning

confidence: 94%

“…1, the L sw -H-G metastable equilibrium line is in actuality an extension of the liquid water-hydrate-gas (L w -H-G) equilibrium line into the temperature region below 273 K in the p-T phase diagram (Mel'nikov et al, 2007;Melnikov et al, 2009Melnikov et al, , 2010Melnikov et al, , 2011Ohno et al, 2011;Vlasov et al, 2013). The region in the p-T phase diagram between the I-H-G equilibrium line and the L sw -H-G metastable equilibrium line is the hydrate metastability region.…”

Section: Introductionmentioning

confidence: 97%

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Study of gas hydrate metastability and its decay for hydrate samples containing unreacted supercooled liquid water below the ice melting point using pulse NMR

Мадыгулов

Nesterov

Reshetnikov

et al. 2015

Chemical Engineering Science

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Section: Resultsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 97%

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Study of gas hydrate metastability and its decay for hydrate samples containing unreacted supercooled liquid water below the ice melting point using pulse NMR

Мадыгулов

Nesterov

Reshetnikov

et al. 2015

Chemical Engineering Science

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“…Water that forms in this case is a metastable phase, and its appearance is related to kinetic difficulties of the direct solid phase transition ice-СО 2 hydrate. We showed earlier [8] that the reverse transition CO 2 hydrate-ice can also take place through the intermediate stage of metastable water formation. It was mentioned above that ice melting was not observed at temperatures below -3.2°C.…”

Section: Influence Of Carbon Dioxide On Melting Of Underground Icementioning

confidence: 96%

“…Description of the installment and experimental technique are given in [7]. This approach on the whole has been successfully applied for studying the phase transitions and equilib riums during formation and dissociation of СО 2 hydrates [8]. The main component of the installment is a high pressure reactor.…”

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confidence: 99%

Influence of carbon dioxide on melting of underground ice

et al. 2014

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One of the global ecological problems related to climate stability of the Earth is the imbalance of green house gases (chiefly methane and carbon dioxide) in the atmosphere, resulting from anthropogenicdomestic and industrial-activity. Among the pro posed solution methods, the possibility of sequestra tion of industrial СО 2 waste by pumping it into the upper lithospheric layers, including frozen and subfro zen horizons, has been studied intensively [1][2][3]. The interaction of carbon dioxide with ice, which is the main component of frozen horizons, remains beyond the scope of these studies, as does the possible influ ence of СО 2 on ice melting and, as a consequence, on permafrost stability and the position of the permafrost rock (PFR) boundary.In contrast to most gases, CO 2 dissolves well in water and its solubility increases with an increase in pressure. Dissolution of СО 2 in water is to decrease the temperature of solution freezing, in comparison to the freezing temperature of pure water; hence, the tem perature of ice melting also decreases. During forma tion of hydrates, the high solubility of CO 2 in water decreases the temperature of the quadrupole point of equilibrium between four phases (ice-gas solution in water-hydrate-gas) in comparison to the formation of hydrates of other, less water soluble gases. Accord ing to various sources, the value of such a decrease isThe aim of the present communication is to pay attention to the role of СО 2 in PFR stability, the posi tion of the permafrost boundary, and the change in the permafrost thickness in the case of possible CO 2 sequestration in frozen and subfrozen horizons. This is made by experimental modeling of ice melting in the СО 2 atmosphere. EXPERIMENTIn our work, we used gaseous СО 2 (99.9 vol. %) and distilled water. To study the behavior of ice specimens in the СО 2 atmosphere, we used the method of visual observation by an optical microscope. In addition to visual observation, we measured pressure р and tem perature T in the studied system. Description of the installment and experimental technique are given in [7]. This approach on the whole has been successfully applied for studying the phase transitions and equilib riums during formation and dissociation of СО 2 hydrates [8]. The main component of the installment is a high pressure reactor. There are windows on the side surface of the reactor, for visual observation of processes running within the reactor. The reactor was placed in a thermostatic chamber to maintain the set temperature within. Ice was obtained by spraying water onto a preliminarily cooled (down to -20°C) transparent plate of organic glass. Water froze and formed ice particles of 1-3 mm in diameter. The reac tor with the plate and ice particles were vacuumized, and then СО 2 was slowly blown into the reactor at the set temperature.The volume of most solids increases when melting; in the case of ice, the volume decreases. Therefore, in accordance with the Clausius-Clapeyron equation, dр/dT = λ/(TΔV), the lower the temperature, th...

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Diffusion model of gas hydrate formation from ice

Власов

2015

Heat Mass Transfer

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Metastable states during dissociation of carbon dioxide hydrates below 273K

Cited by 59 publications

References 12 publications

Study of gas hydrate metastability and its decay for hydrate samples containing unreacted supercooled liquid water below the ice melting point using pulse NMR

Study of gas hydrate metastability and its decay for hydrate samples containing unreacted supercooled liquid water below the ice melting point using pulse NMR

Influence of carbon dioxide on melting of underground ice

Diffusion model of gas hydrate formation from ice

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