Self-preservation of methane hydrate revealed immediately below the eutectic temperature of the mother electrolyte solution

Satō, Hiroshi; Sakamoto, H.; Ogino, Shotaro; Mimachi, Hiroko; Kinoshita, Takahiro; Iwasaki, Toshiki; Sano, Kohei; Ohgaki, Kazunari

doi:10.1016/j.ces.2013.01.014

Cited by 38 publications

(13 citation statements)

References 19 publications

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“…The self-preservation concept was also found in electrolyte systems. At 1 atm, the phenomenon was observed at temperature region below the eutectic point of the system and dissociation rates increased greatly once the eutectic temperature was exceeded [90]. This phenomenon could potentially hinder thermal stimulation or depressurization recovery method if inappropriate conditions are applied.…”

Section: Self-preservation Phenomenamentioning

confidence: 97%

Review of natural gas hydrates as an energy resource: Prospects and challenges

et al. 2016

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Section: Self-preservation Phenomenamentioning

confidence: 97%

Review of natural gas hydrates as an energy resource: Prospects and challenges

et al. 2016

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“…Sato et al . 24,25 , have examined the decomposition rates of methane hydrate in the presence of dilute electrolyte solutions (≤34 mol/m 3 ), in the temperature range 233 to 273 K, and reported that the decomposition is remarkably suppressed (slower than hydrates with pure water) immediately below the eutectic temperature. Authors have also observed a brief upsurge in the decomposition rate at the eutectic temperature.…”

Section: Introductionmentioning

confidence: 99%

Self-preservation and Stability of Methane Hydrates in the Presence of NaCl

Prasad

Kiran

2019

Sci Rep

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Gas hydrate, a solid transformed from an ensemble of water and gaseous molecules under suitable thermodynamic conditions, is present in marine and permafrost strata. The ability of methane hydrates to exist outside of its standard stability zone is vital in many aspects, such as its utility in gas storage and transportation, hydrate-related climate changes and gas reservoirs on the planet. A systematic study on the stability of methane hydrates divulges that the gas uptake decreased by about 10% by increasing the NaCl content to 5.0 wt%. The hydrate formation kinetic is relatively slower in a system with higher NaCl. The self-preservation temperature window for hydrate systems with NaCl 1.5, 3.0 and 5.0 wt% dramatically shifted to a lower temperature (252 K), while it remained around 270 K for NaCl 0.0 and 0.5 wt%. Based on powder x-ray diffraction and micro-Raman spectroscopic studies, the presence of hydrohalite (NaCl·2H 2 O) phase was identified along with the usual hydrate and ice phases. The eutectic melting of this mixture is responsible for shifting the hydrate stability to 252 K. A systematic lattice expansion of cubic phase infers the interaction between NaCl and water molecules of hydrate cages.

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“…There are several factors that control the rate of hydrate dissociation, such as experimental temperature (Stern et al, 2001(Stern et al, , 2003 and pressure (Komai et al, 2004). Further, composition of the feed gas (Stern et al, 2003;Takeya and Ripmeester, 2010;Uchida et al, 2011), hydrate granular size (Takeya et al, 2005;Mimachi et al, 2014) and co-existence of certain additives or electrolytes (Zhang and Rogers, 2008;Takeya et al, 2012;Sato et al, 2013), and presence of fine glass beads (Hachikubo et al, 2011) in hydrate forming systems also influence the dissociation process. The effect of temperature on the dissociation process is exhaustively studied in the past by Stern et al (2001) and they reported significantly slower at atmospheric pressure in a temperature window 241e271 K (generally known as self-preservation window), with two minima at 249 and 269 K. Nakoryakov and Misyura (2013) have reported that the thermal dissociation rate is significantly lower in natural hydrates compare to synthetic analogues in self preservation window despite of structural similarity.…”

Section: Introductionmentioning

confidence: 96%