Dissociation of Fresh- And Seawater Hydrates along the Phase Boundaries between 2.3 and 17 MPa

Loh, Matilda; Falser, Simon; Babu, P. Ramesh; Linga, Praveen; Palmer, Andrew; Tan, Thiam Soon

doi:10.1021/ef3008954

Cited by 34 publications

(39 citation statements)

References 24 publications

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“…The presence of salts in seawater acts as a thermodynamic inhibitor, depressing the dissociation temperature of methane hydrate by a small amount compared to the freshwater system. 25 Phase boundaries of methane hydrates in fresh water and sea water are plotted using published data 13 in Figure S1, to account for the dissociation Similarly, there would be a net decrease in the substrate concentration, and a net decrease in the oxygen concentration. It is important to note that the net heat is also negative, making the overall bioreaction endothermic.…”

Section: Near-equilibrium Energy Balance Simulationsmentioning

confidence: 99%

Microbe-Worm Symbiosis Stabilizes Methane Hydrates in Deep Marine Environments

Hua

Ahmad

Choezin

et al. 2021

Preprint

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Our Planet has a natural ecosystem comprised of living organisms and methane hydrates in deep marine environments. This ecosystem was constructed in the present work to examine the influence that subtle temperature fluctuations could have on the dynamic stability of the hydrate deposits. The coupled mass and energy balance equations that describe the microbial bioreactions, their consumption by feather duster worms, and methane hydrate dissociation confirm that the bioreaction kinetics are dominated by endothermic methanogenic metabolism that stabilizes methane hydrates with a fragile tolerance to 0.001K temperature increases. The feather duster worms also stabilize the hydrates via their selective consumption of methanotrophs that could otherwise overtake the system by their exothermic metabolism. Critical ocean temperature limits exist, beyond which hydrate dissociations would cause underwater eruptions of methane into the sea. Historical ocean temperature records and gas hydrate inventory estimates combined with our model suggests that hydrate deposits as deep as 560-meters below sea level could already be at risk, whereas the methane hydrate stability zone will retreat deeper as ocean temperatures rise. Slowing its retreat could avoid the massive release of greenhouse gas.

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Section: Near-equilibrium Energy Balance Simulationsmentioning

confidence: 99%

Microbe-Worm Symbiosis Stabilizes Methane Hydrates in Deep Marine Environments

Hua

Ahmad

Choezin

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…The presence of salts in seawater acts as a thermodynamic inhibitor, depressing the dissociation temperature of methane hydrate by a small amount compared to the freshwater system. 25 Phase boundaries of methane hydrates in fresh water and sea water are plotted using published data 13 in Figure S1, to account for the dissociation temperature depression in sea water. At a depth of 485 m, the corresponding pressure of 50 bar and temperature of 278.4 K yield Figure 3a.…”

Section: Near-equilibrium Energy Balance Simulationsmentioning

confidence: 99%

Microbe-Worm Symbiosis Stabilizes Methane Hydrates in Deep Marine Environments

et al. 2021

View full text Add to dashboard Cite

Our planet has a natural ecosystem comprised of living organisms and methane hydrates in deep marine environments. This ecosystem was constructed in the present work to examine the influence that subtle temperature fluctuations could have on the dynamic stability of the hydrate deposits. The coupled mass and energy balance equations that describe the microbial bioreactions, their consumption by feather duster worms, and methane hydrate dissociation confirm that the bioreaction kinetics is dominated by endothermic methanogenic metabolism that stabilizes methane hydrates with a fragile tolerance to 0.001 K temperature increases. The feather duster worms also stabilize the hydrates via their selective consumption of methanotrophs that could otherwise overtake the system by their exothermic metabolism. Critical ocean temperature limits exist, beyond which hydrate dissociations would cause underwater eruptions of methane into the sea. Historical ocean temperature records and gas hydrate inventory estimates combined with our model suggest that hydrate deposits as deep as 560 m below sea level could already be at risk, whereas the methane hydrate stability zone will retreat deeper as the ocean temperature rises. Slowing its retreat could avoid the massive release of greenhouse gas.

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“…The PVT sapphire cell apparatus was used to measure the hydrate dissociation conditions by employing the temperature search method as an experimental determination technique (Kim et al 2011;Loh et al 2012;Smith et al 2015;AlHarooni et al 2015;Smith et al 2016). Experimentally, the PVT cell was maintained at a constant pressure using the piston pump and keeping the valve to the PVT cell open.…”

Section: Fig 1 Schematic Of the Pvt Sapphire Cellmentioning

confidence: 99%

Experimental determination of hydrate phase equilibrium for different gas mixtures containing methane, carbon dioxide and nitrogen with motor current measurements

Sadeq

Iglauer

Lebedev

et al. 2017

Journal of Natural Gas Science and Engineering

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Hydrate dissociation equilibrium conditions for carbon dioxide + methane with water, nitrogen + methane with water and carbon dioxide + nitrogen with water were measured using cryogenic sapphire cell.Measurements were performed in the temperature range of 275.75K to 293.95K and for pressures ranging from 5 MPa to 25 MPa. The resulting data indicate that as the carbon dioxide concentration is increased in the gas mixture, the gas hydrate equilibrium temperature increases. In contrast, by increasing the nitrogen concentration in the gas mixtures containing methane or carbon dioxide decreased the gas hydrate equilibrium temperatures. Furthermore, the cage occupancies for the carbon dioxide + methane system were evaluated using the Van der Waals and Platteeuw thermodynamic theory with the Langmuir adsorption model and Peng-Robinson equation of state. The data demonstrated the increasing promoting effect of carbon dioxide with its concentration.In addition, the motor current changes during the hydrate formation and dissociation processes were measured by keeping the rotation speed of the magnetic stirrer that was connected to a DC motor constant.The motor current measurements were reported and it showed that the hydrate plug formation and dissociation could be predicted by the changes in the motor current.

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Dissociation of Fresh- And Seawater Hydrates along the Phase Boundaries between 2.3 and 17 MPa

Cited by 34 publications

References 24 publications

Microbe-Worm Symbiosis Stabilizes Methane Hydrates in Deep Marine Environments

Microbe-Worm Symbiosis Stabilizes Methane Hydrates in Deep Marine Environments

Microbe-Worm Symbiosis Stabilizes Methane Hydrates in Deep Marine Environments

Experimental determination of hydrate phase equilibrium for different gas mixtures containing methane, carbon dioxide and nitrogen with motor current measurements

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